To solve these problems, we need to find the area of each circle.
The formula for the area of a circle is:
Area = π × r²
Where:
*
π (pi) is approximately
3.14159.
*
r is the radius (the distance from the center to the edge).
Let's work through each problem step-by-step. We will use 3.14159 for pi and round our final answers to one decimal place, just like in the example.
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Problem 2:
*
Radius (r): The image shows the line goes from the center to the edge, labeled
12 cm.
*
Formula: Area = π × 12²
*
Calculation:
* First, square the radius: $12 \times 12 = 144$
* Next, multiply by pi: $144 \times 3.14159 \approx 452.389$
* Rounding to one decimal place:
452.4
Problem 3:
*
Radius (r): The image shows the line goes from the center to the edge, labeled
8 cm.
*
Formula: Area = π × 8²
*
Calculation:
* First, square the radius: $8 \times 8 = 64$
* Next, multiply by pi: $64 \times 3.14159 \approx 201.062$
* Rounding to one decimal place:
201.1
Problem 4:
*
Radius (r): The image shows the line goes from the center to the edge, labeled
10 cm.
*
Formula: Area = π × 10²
*
Calculation:
* First, square the radius: $10 \times 10 = 100$
* Next, multiply by pi: $100 \times 3.14159 = 314.159$
* Rounding to one decimal place:
314.2
Problem 5:
*
Radius (r): The image shows the line goes from the center to the edge, labeled
5 cm.
*
Formula: Area = π × 5²
*
Calculation:
* First, square the radius: $5 \times 5 = 25$
* Next, multiply by pi: $25 \times 3.14159 \approx 78.539$
* Rounding to one decimal place:
78.5
Problem 6:
*
Radius (r): The image shows the line goes from the center to the edge, labeled
4 cm.
*
Formula: Area = π × 4²
*
Calculation:
* First, square the radius: $4 \times 4 = 16$
* Next, multiply by pi: $16 \times 3.14159 \approx 50.265$
* Rounding to one decimal place:
50.3
Final Answer:
2) 452.4 cm²
3) 201.1 cm²
4) 314.2 cm²
5) 78.5 cm²
6) 50.3 cm²
Parent Tip: Review the logic above to help your child master the concept of circumference and area worksheet 1.
