This geometry worksheet offers practice problems for calculating the area of regular polygons like pentagons and hexagons, as well as composite shapes.
Worksheet for finding the area of regular polygons and composite figures including pentagons, hexagons, and shapes with semicircles.
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Step-by-step solution for: Area of Composite Figures Worksheets - Math Monks
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Show Answer Key & Explanations
Step-by-step solution for: Area of Composite Figures Worksheets - Math Monks
To solve the problems in the worksheet, we need to calculate the areas of various regular polygons and composite figures. Let's go through each problem step by step.
---
The given figure is a rectangle with dimensions:
- Length = 10.9 m
- Width = 7.5 m
The area of a rectangle is given by:
\[
\text{Area} = \text{Length} \times \text{Width}
\]
\[
\text{Area} = 10.9 \, \text{m} \times 7.5 \, \text{m} = 81.75 \, \text{m}^2
\]
Answer for Problem 1:
\[
\boxed{81.75 \, \text{m}^2}
\]
---
The given figure is a regular pentagon with:
- Side length = 13.2 yd
- Apothem = 3.5 yd
The area of a regular polygon is given by:
\[
\text{Area} = \frac{1}{2} \times \text{Perimeter} \times \text{Apothem}
\]
For a pentagon, the perimeter is:
\[
\text{Perimeter} = 5 \times \text{Side length} = 5 \times 13.2 \, \text{yd} = 66 \, \text{yd}
\]
Thus, the area is:
\[
\text{Area} = \frac{1}{2} \times 66 \, \text{yd} \times 3.5 \, \text{yd} = 33 \, \text{yd} \times 3.5 \, \text{yd} = 115.5 \, \text{yd}^2
\]
Answer for Problem 2:
\[
\boxed{115.5 \, \text{yd}^2}
\]
---
The given figure is a regular hexagon with:
- Side length = 12 cm
- Apothem = \(5\sqrt{3} \, \text{cm}\)
The area of a regular polygon is given by:
\[
\text{Area} = \frac{1}{2} \times \text{Perimeter} \times \text{Apothem}
\]
For a hexagon, the perimeter is:
\[
\text{Perimeter} = 6 \times \text{Side length} = 6 \times 12 \, \text{cm} = 72 \, \text{cm}
\]
Thus, the area is:
\[
\text{Area} = \frac{1}{2} \times 72 \, \text{cm} \times 5\sqrt{3} \, \text{cm} = 36 \, \text{cm} \times 5\sqrt{3} \, \text{cm} = 180\sqrt{3} \, \text{cm}^2
\]
Answer for Problem 3:
\[
\boxed{180\sqrt{3} \, \text{cm}^2}
\]
---
The given figure is a triangle with:
- Base = 22 in
- Height = 16 in
The area of a triangle is given by:
\[
\text{Area} = \frac{1}{2} \times \text{Base} \times \text{Height}
\]
\[
\text{Area} = \frac{1}{2} \times 22 \, \text{in} \times 16 \, \text{in} = 11 \, \text{in} \times 16 \, \text{in} = 176 \, \text{in}^2
\]
Answer for Problem 4:
\[
\boxed{176 \, \text{in}^2}
\]
---
The given figure consists of a rectangle and a semi-circle:
- Rectangle dimensions: Length = 32 ft, Width = 18 ft
- Semi-circle diameter = 18 ft (same as the width of the rectangle)
#### Step 1: Area of the rectangle
\[
\text{Area}_{\text{rectangle}} = \text{Length} \times \text{Width} = 32 \, \text{ft} \times 18 \, \text{ft} = 576 \, \text{ft}^2
\]
#### Step 2: Area of the semi-circle
The radius of the semi-circle is:
\[
r = \frac{\text{Diameter}}{2} = \frac{18 \, \text{ft}}{2} = 9 \, \text{ft}
\]
The area of a full circle is:
\[
\text{Area}_{\text{circle}} = \pi r^2 = \pi (9 \, \text{ft})^2 = 81\pi \, \text{ft}^2
\]
The area of the semi-circle is half of this:
\[
\text{Area}_{\text{semi-circle}} = \frac{1}{2} \times 81\pi \, \text{ft}^2 = 40.5\pi \, \text{ft}^2
\]
#### Step 3: Total area
\[
\text{Total Area} = \text{Area}_{\text{rectangle}} + \text{Area}_{\text{semi-circle}} = 576 \, \text{ft}^2 + 40.5\pi \, \text{ft}^2
\]
Answer for Problem 5:
\[
\boxed{576 + 40.5\pi \, \text{ft}^2}
\]
---
The given figure is a trapezoid with:
- Bases: \(b_1 = 9 \, \text{mm}\), \(b_2 = 9 \, \text{mm}\) (both bases are equal, so it's actually a parallelogram)
- Height = 12 mm
The area of a trapezoid (or parallelogram) is given by:
\[
\text{Area} = \text{Base} \times \text{Height}
\]
\[
\text{Area} = 9 \, \text{mm} \times 12 \, \text{mm} = 108 \, \text{mm}^2
\]
Answer for Problem 6:
\[
\boxed{108 \, \text{mm}^2}
\]
---
The given figure consists of a rectangle and a triangle:
- Rectangle dimensions: Length = 10 km, Width = 6 km
- Triangle base = 4.8 km, Height = 6 km (same as the width of the rectangle)
#### Step 1: Area of the rectangle
\[
\text{Area}_{\text{rectangle}} = \text{Length} \times \text{Width} = 10 \, \text{km} \times 6 \, \text{km} = 60 \, \text{km}^2
\]
#### Step 2: Area of the triangle
\[
\text{Area}_{\text{triangle}} = \frac{1}{2} \times \text{Base} \times \text{Height} = \frac{1}{2} \times 4.8 \, \text{km} \times 6 \, \text{km} = 2.4 \, \text{km} \times 6 \, \text{km} = 14.4 \, \text{km}^2
\]
#### Step 3: Total area
\[
\text{Total Area} = \text{Area}_{\text{rectangle}} + \text{Area}_{\text{triangle}} = 60 \, \text{km}^2 + 14.4 \, \text{km}^2 = 74.4 \, \text{km}^2
\]
Answer for Problem 7:
\[
\boxed{74.4 \, \text{km}^2}
\]
---
The given figure consists of a square with a triangle removed:
- Square side length = 16 cm
- Triangle base = 11.5 cm, Height = 8.5 cm
#### Step 1: Area of the square
\[
\text{Area}_{\text{square}} = \text{Side}^2 = 16 \, \text{cm} \times 16 \, \text{cm} = 256 \, \text{cm}^2
\]
#### Step 2: Area of the triangle
\[
\text{Area}_{\text{triangle}} = \frac{1}{2} \times \text{Base} \times \text{Height} = \frac{1}{2} \times 11.5 \, \text{cm} \times 8.5 \, \text{cm} = 5.75 \, \text{cm} \times 8.5 \, \text{cm} = 48.875 \, \text{cm}^2
\]
#### Step 3: Total area
\[
\text{Total Area} = \text{Area}_{\text{square}} - \text{Area}_{\text{triangle}} = 256 \, \text{cm}^2 - 48.875 \, \text{cm}^2 = 207.125 \, \text{cm}^2
\]
Answer for Problem 8:
\[
\boxed{207.125 \, \text{cm}^2}
\]
---
1. \(\boxed{81.75 \, \text{m}^2}\)
2. \(\boxed{115.5 \, \text{yd}^2}\)
3. \(\boxed{180\sqrt{3} \, \text{cm}^2}\)
4. \(\boxed{176 \, \text{in}^2}\)
5. \(\boxed{576 + 40.5\pi \, \text{ft}^2}\)
6. \(\boxed{108 \, \text{mm}^2}\)
7. \(\boxed{74.4 \, \text{km}^2}\)
8. \(\boxed{207.125 \, \text{cm}^2}\)
---
Problem 1: Rectangle
The given figure is a rectangle with dimensions:
- Length = 10.9 m
- Width = 7.5 m
The area of a rectangle is given by:
\[
\text{Area} = \text{Length} \times \text{Width}
\]
\[
\text{Area} = 10.9 \, \text{m} \times 7.5 \, \text{m} = 81.75 \, \text{m}^2
\]
Answer for Problem 1:
\[
\boxed{81.75 \, \text{m}^2}
\]
---
Problem 2: Regular Pentagon
The given figure is a regular pentagon with:
- Side length = 13.2 yd
- Apothem = 3.5 yd
The area of a regular polygon is given by:
\[
\text{Area} = \frac{1}{2} \times \text{Perimeter} \times \text{Apothem}
\]
For a pentagon, the perimeter is:
\[
\text{Perimeter} = 5 \times \text{Side length} = 5 \times 13.2 \, \text{yd} = 66 \, \text{yd}
\]
Thus, the area is:
\[
\text{Area} = \frac{1}{2} \times 66 \, \text{yd} \times 3.5 \, \text{yd} = 33 \, \text{yd} \times 3.5 \, \text{yd} = 115.5 \, \text{yd}^2
\]
Answer for Problem 2:
\[
\boxed{115.5 \, \text{yd}^2}
\]
---
Problem 3: Regular Hexagon
The given figure is a regular hexagon with:
- Side length = 12 cm
- Apothem = \(5\sqrt{3} \, \text{cm}\)
The area of a regular polygon is given by:
\[
\text{Area} = \frac{1}{2} \times \text{Perimeter} \times \text{Apothem}
\]
For a hexagon, the perimeter is:
\[
\text{Perimeter} = 6 \times \text{Side length} = 6 \times 12 \, \text{cm} = 72 \, \text{cm}
\]
Thus, the area is:
\[
\text{Area} = \frac{1}{2} \times 72 \, \text{cm} \times 5\sqrt{3} \, \text{cm} = 36 \, \text{cm} \times 5\sqrt{3} \, \text{cm} = 180\sqrt{3} \, \text{cm}^2
\]
Answer for Problem 3:
\[
\boxed{180\sqrt{3} \, \text{cm}^2}
\]
---
Problem 4: Triangle
The given figure is a triangle with:
- Base = 22 in
- Height = 16 in
The area of a triangle is given by:
\[
\text{Area} = \frac{1}{2} \times \text{Base} \times \text{Height}
\]
\[
\text{Area} = \frac{1}{2} \times 22 \, \text{in} \times 16 \, \text{in} = 11 \, \text{in} \times 16 \, \text{in} = 176 \, \text{in}^2
\]
Answer for Problem 4:
\[
\boxed{176 \, \text{in}^2}
\]
---
Problem 5: Composite Figure (Rectangle + Semi-circle)
The given figure consists of a rectangle and a semi-circle:
- Rectangle dimensions: Length = 32 ft, Width = 18 ft
- Semi-circle diameter = 18 ft (same as the width of the rectangle)
#### Step 1: Area of the rectangle
\[
\text{Area}_{\text{rectangle}} = \text{Length} \times \text{Width} = 32 \, \text{ft} \times 18 \, \text{ft} = 576 \, \text{ft}^2
\]
#### Step 2: Area of the semi-circle
The radius of the semi-circle is:
\[
r = \frac{\text{Diameter}}{2} = \frac{18 \, \text{ft}}{2} = 9 \, \text{ft}
\]
The area of a full circle is:
\[
\text{Area}_{\text{circle}} = \pi r^2 = \pi (9 \, \text{ft})^2 = 81\pi \, \text{ft}^2
\]
The area of the semi-circle is half of this:
\[
\text{Area}_{\text{semi-circle}} = \frac{1}{2} \times 81\pi \, \text{ft}^2 = 40.5\pi \, \text{ft}^2
\]
#### Step 3: Total area
\[
\text{Total Area} = \text{Area}_{\text{rectangle}} + \text{Area}_{\text{semi-circle}} = 576 \, \text{ft}^2 + 40.5\pi \, \text{ft}^2
\]
Answer for Problem 5:
\[
\boxed{576 + 40.5\pi \, \text{ft}^2}
\]
---
Problem 6: Trapezoid
The given figure is a trapezoid with:
- Bases: \(b_1 = 9 \, \text{mm}\), \(b_2 = 9 \, \text{mm}\) (both bases are equal, so it's actually a parallelogram)
- Height = 12 mm
The area of a trapezoid (or parallelogram) is given by:
\[
\text{Area} = \text{Base} \times \text{Height}
\]
\[
\text{Area} = 9 \, \text{mm} \times 12 \, \text{mm} = 108 \, \text{mm}^2
\]
Answer for Problem 6:
\[
\boxed{108 \, \text{mm}^2}
\]
---
Problem 7: Composite Figure (Rectangle + Triangle)
The given figure consists of a rectangle and a triangle:
- Rectangle dimensions: Length = 10 km, Width = 6 km
- Triangle base = 4.8 km, Height = 6 km (same as the width of the rectangle)
#### Step 1: Area of the rectangle
\[
\text{Area}_{\text{rectangle}} = \text{Length} \times \text{Width} = 10 \, \text{km} \times 6 \, \text{km} = 60 \, \text{km}^2
\]
#### Step 2: Area of the triangle
\[
\text{Area}_{\text{triangle}} = \frac{1}{2} \times \text{Base} \times \text{Height} = \frac{1}{2} \times 4.8 \, \text{km} \times 6 \, \text{km} = 2.4 \, \text{km} \times 6 \, \text{km} = 14.4 \, \text{km}^2
\]
#### Step 3: Total area
\[
\text{Total Area} = \text{Area}_{\text{rectangle}} + \text{Area}_{\text{triangle}} = 60 \, \text{km}^2 + 14.4 \, \text{km}^2 = 74.4 \, \text{km}^2
\]
Answer for Problem 7:
\[
\boxed{74.4 \, \text{km}^2}
\]
---
Problem 8: Composite Figure (Square - Triangle)
The given figure consists of a square with a triangle removed:
- Square side length = 16 cm
- Triangle base = 11.5 cm, Height = 8.5 cm
#### Step 1: Area of the square
\[
\text{Area}_{\text{square}} = \text{Side}^2 = 16 \, \text{cm} \times 16 \, \text{cm} = 256 \, \text{cm}^2
\]
#### Step 2: Area of the triangle
\[
\text{Area}_{\text{triangle}} = \frac{1}{2} \times \text{Base} \times \text{Height} = \frac{1}{2} \times 11.5 \, \text{cm} \times 8.5 \, \text{cm} = 5.75 \, \text{cm} \times 8.5 \, \text{cm} = 48.875 \, \text{cm}^2
\]
#### Step 3: Total area
\[
\text{Total Area} = \text{Area}_{\text{square}} - \text{Area}_{\text{triangle}} = 256 \, \text{cm}^2 - 48.875 \, \text{cm}^2 = 207.125 \, \text{cm}^2
\]
Answer for Problem 8:
\[
\boxed{207.125 \, \text{cm}^2}
\]
---
Final Answers:
1. \(\boxed{81.75 \, \text{m}^2}\)
2. \(\boxed{115.5 \, \text{yd}^2}\)
3. \(\boxed{180\sqrt{3} \, \text{cm}^2}\)
4. \(\boxed{176 \, \text{in}^2}\)
5. \(\boxed{576 + 40.5\pi \, \text{ft}^2}\)
6. \(\boxed{108 \, \text{mm}^2}\)
7. \(\boxed{74.4 \, \text{km}^2}\)
8. \(\boxed{207.125 \, \text{cm}^2}\)
Parent Tip: Review the logic above to help your child master the concept of compound shapes worksheet with answers.