To find the area of a triangle, we use this simple formula:
Area = (base × height) ÷ 2
The “base” is the bottom side of the triangle.
The “height” is the straight line from the base up to the top corner — and it must be perpendicular (make a right angle) with the base. In all these problems, the height is already drawn for you with a little square showing the right angle.
Let’s solve each one step by step.
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Problem 1:
Base = 8 ft
Height = 2 ft
Area = (8 × 2) 2 = 16 ÷ 2 =
8 ft²
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Problem 2:
Base = 11 m
Height = 9 m
Area = (11 × 9) ÷ 2 = 99 ÷ 2 =
49.5 m²
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Problem 3:
Base = 19 ft
Height = 13 ft
Area = (19 × 13) ÷ 2
First, 19 × 13:
19 × 10 = 190
19 × 3 = 57
190 + 57 = 247
Then, 247 ÷ 2 =
123.5 ft²
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Problem 4:
Base = 36 m
Height = 27 m
Area = (36 × 27) ÷ 2
First, 36 × 27:
We can do 36 × 20 = 720
36 × 7 = 252
720 + 252 = 972
Then, 972 ÷ 2 =
486 m²
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Problem 5:
Base = 5 cm
Height = 6 cm
Area = (5 × 6) ÷ 2 = 30 ÷ 2 =
15 cm²
*(Note: Even though the height is drawn outside the triangle, it still counts as long as it’s perpendicular to the base extended.)*
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Problem 6:
Base = 33 m
Height = 11 m
Area = (33 × 11) ÷ 2
33 × 11 = 363
363 ÷ 2 =
181.5 m²
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Problem 7:
Base = 27 cm
Height = 9 cm
Area = (27 × 9) ÷ 2
27 × 9 = 243
243 ÷ 2 =
121.5 cm²
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Problem 8:
Base = 3 m
Height = 16 m
Area = (3 × 16) ÷ 2 = 48 ÷ 2 =
24 m²
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Final Answer:
1. 8 ft²
2. 49.5 m²
3. 123.5 ft²
4. 486 m²
5. 15 cm²
6. 181.5 m²
7. 121.5 cm²
8. 24 m²
Parent Tip: Review the logic above to help your child master the concept of area of triangles worksheet.
