1. Which of the following is the formula to find the area of a circle?
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1 point
a. C = 2 x pi x r
b. A = pi x r x r
c. A = l x w x h
d. A = s x s x s
2. A circular rug has a radius of 5cm radius. Find the area of the rug.
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1 point
a. 78.5 sq. cm
b. 785 sq. cm
c. 31.4 sq. cm
314 sq. cm
3. A dining bowl is 20 cm in diameter. What is its area?
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1 point
a. 31.4 sq. cm
b. 314 sq. cm
c. 125.6 sq. cm
d. 1 256 sq. cm
4. What is the area of a wall clock if its radius is 2.5 cm?
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1 point
a.1.9625 sq. cm
b. 196.25 sq. cm
c. 19.625 sq. cm
d. 1 9625 sq. cm
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Answer:
1. B. A = πr² or pi × r × r
2. A = πr²
= (3.14)(5cm)²
= (3.14)(25cm²)
A = 78.5 sq. cm or 78.5cm² (A)
3. r = d/2
= 20cm/2
r = 10cm
A = πr²
= (3.14)(10cm)²
= (3.14)(100cm²)
A = 314 sq. cm or 314cm² (B)
4. A = πr²
= (3.14)(2.5cm)²
= (3.14)(6.25cm²)
A = 19.625 sq. cm or 19.625cm² (C)