A piece of wire 72 cm long is cut into two equal pieces and each is formed into a circle. What is the sum, in square centimeters, of the areas of these circles?
A piece of wire 72 cm long is cut into two equal pieces and each is formed into a circle. What is the sum, in square centimeters, of the areas of these circles?
Figure the area of one circle then double it.
One circle has a circumference of 36.
Circumference = diameter • π = 2 • radius • π
36 = 2 • r • π
r = 36 / 2π = 18 / π
Area = π • r2
Area = π • (18 / π )2
Area = π • 182 / π2
Area = 182 / π
It's time to substitute the value of pi ..... let's call it 3.1416
Area = 324 / 3.1416 = 103.13 rounded to 2 decimal places
Area of two circles this size = 2 • 103.13 = 206.26 cm2
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