ANSWER: Radii lines

OB

OD

OF

are all radii not any others.

OH

Radius = 10 units

A = r2 r = 8 feet

A = 3.14 x 82 (8 x 8)

A = 3.14 x 64

A = 200.96 square feet

PROBLEMS IN AREA OF A CIRCLE

A = π r2

(1) Find the area of four circles whose radii are as follows:

a. 5 inches.

b. 7 feet.

c. 6 yards.

d. 4.5 inches.

(2) What is the area of a cross section of petroleum pipe whose radius is 3

inches?

(3) The diameter of a circulartop table is 2 feet; what is its area?

(4) In making the bottom of a cup, a tinsmith cuts out a circle 3 inches in

diameter from a square piece of tin whose side is 3 inches. What is the area of

the bottom of the cup? How much tin is wasted?

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