Question

Find the area of the following circles. a. A circle with a 8-inch radius b. A circle with a 10-kilometer radius c. A circle with a 14-yard diameter d. A circle with a 22-centimeter diameter

Answer 1

Answer: A. 201.14inches²

B. 314.28km²

C. 154yds²

D. 380cm²

Step-by-step explanation: the area of a circle is given by [pie] (22/7) multiplied by the square of the radius

Radius is half the diameter of the circle

Applying the formula 22/7 x r²:

A. 22/7 x 8² = 201.4inch²

B. 22/7 x 10² = 314.28km²

C. 22/7 x (14/2)² = 154yd²

D. 22/7 x (22/2)² = 380cm²

Kudos!

Answer 2

Area of a circle is $A= \pi r^2$.  The first one, a, the radius squared is 8*8=64.  So $A=64 \pi$.  If you multiply in pi as 3.14, you'll have 200.96 square inches.  The second one, b, the radius squared is 10*10=100.  So $A=100 \pi$ square kilometers.  If you multiply in pi as 3.14 you'll have 314 square kilometers.  The third one, c, the radius squared is 14*14=196.  So $A=196 \pi yd^2$.  Or you could multiply in pi as 3.14 to get 615.44 yd squared.  For the last one, d, the radius squared is 22*22=484 cm.  Therefore, $A=484 \pi cm^2$, or multiply in 3.14 for pi to get 1519.76 cm squared.  There you go!