To find the area of each circle, we use the formula:
Area = π × r²
We are told to use
π = 3.14.
Let’s solve each one step by step.
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Problem 1:
Radius (r) = 7 in
Area = 3.14 × 7² = 3.14 × 49 =
153.86 in²
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Problem 2:
Radius (r) = 5 cm
Area = 3.14 × 5² = 3.14 × 25 =
78.5 cm²
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Problem 3:
Diameter = 8 ft → Radius = 8 ÷ 2 = 4 ft
Area = 3.14 × 4² = 3.14 × 16 =
50.24 ft²
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Problem 4:
Radius (r) = 10 m
Area = 3.14 × 10² = 3.14 × 100 =
314 m²
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Problem 5:
Diameter = 14 mm → Radius = 14 ÷ 2 = 7 mm
Area = 3.14 × 7² = 3.14 × 49 =
153.86 mm²
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Problem 6:
Radius (r) = 9 yd
Area = 3.14 × 9² = 3.14 × 81 =
254.34 yd²
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Problem 7:
Diameter = 12 km → Radius = 12 ÷ 2 = 6 km
Area = 3.14 × 6² = 3.14 × 36 =
113.04 km²
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Problem 8:
Radius (r) = 1.5 mi
Area = 3.14 × (1.5)² = 3.14 × 2.25 =
7.065 mi²
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Problem 9:
Diameter = 20 in → Radius = 20 ÷ 2 = 10 in
Area = 3.14 × 10² = 3.14 × 100 =
314 in²
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Final Answer:
1. 153.86 in²
2. 78.5 cm²
3. 50.24 ft²
4. 314 m²
5. 153.86 mm²
6. 254.34 yd²
7. 113.04 km²
8. 7.065 mi²
9. 314 in²
Parent Tip: Review the logic above to help your child master the concept of finding the area of a circle worksheet.
