Here are the step-by-step solutions for each problem on the worksheet.
Important Rule: The formula for the area of a circle is $A = \pi r^2$.
* If you are given the
radius ($r$), square it and multiply by $3.14$.
* If you are given the
diameter (the line all the way across), divide it by 2 first to get the radius.
* Round your final answer to two decimal places (nearest hundredth).
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1. Given: Diameter $H = 22$ ft
* First, find the radius: $22 \div 2 = 11$ ft.
* Square the radius: $11 \times 11 = 121$.
* Multiply by $\pi$ ($3.14$): $121 \times 3.14 = 379.94$.
*
Area = 379.94 sq ft
2. Given: Radius $J = 8$ ft
* The letter $J$ goes from the center to the edge, so it is the radius.
* Square the radius: $8 \times 8 = 64$.
* Multiply by $\pi$ ($3.14$): $64 \times 3.14 = 200.96$.
*
Area = 200.96 sq ft
3. Given: Radius $F = 21$ m
* The letter $F$ goes from the center to the edge, so it is the radius.
* Square the radius: $21 \times 21 = 441$.
* Multiply by $\pi$ ($3.14$): $441 \times 3.14 = 1384.74$.
*
Area = 1384.74 sq m
4. Given: Diameter $t = 6$ yd
* First, find the radius: $6 \div 2 = 3$ yd.
* Square the radius: $3 \times 3 = 9$.
* Multiply by $\pi$ ($3.14$): $9 \times 3.14 = 28.26$.
*
Area = 28.26 sq yd
5. Given: Radius $Q = 31$ m
* The letter $Q$ goes from the center to the edge, so it is the radius.
* Square the radius: $31 \times 31 = 961$.
* Multiply by $\pi$ ($3.14$): $961 \times 3.14 = 3017.54$.
*
Area = 3017.54 sq m
6. Given: Diameter $i = 14$ yd
* First, find the radius: $14 \div 2 = 7$ yd.
* Square the radius: $7 \times 7 = 49$.
* Multiply by $\pi$ ($3.14$): $49 \times 3.14 = 153.86$.
*
Area = 153.86 sq yd
7. Given: Radius $b = 19$ m
* The letter $b$ goes from the center to the edge, so it is the radius.
* Square the radius: $19 \times 19 = 361$.
* Multiply by $\pi$ ($3.14$): $361 \times 3.14 = 1133.54$.
*
Area = 1133.54 sq m
8. Given: Diameter $a = 28$ ft
* First, find the radius: $28 \div 2 = 14$ ft.
* Square the radius: $14 \times 14 = 196$.
* Multiply by $\pi$ ($3.14$): $196 \times 3.14 = 615.44$.
*
Area = 615.44 sq ft
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Final Answer:
1. 379.94 sq ft
2. 200.96 sq ft
3. 1384.74 sq m
4. 28.26 sq yd
5. 3017.54 sq m
6. 153.86 sq yd
7. 1133.54 sq m
8. 615.44 sq ft
Parent Tip: Review the logic above to help your child master the concept of area of a circle worksheet.
