A bicycle training wheel has a radius of 3 inches. A regular bicycle wheel has a radius of 10 inches.

Question

Approximately how much smaller, in square inches and rounded to the nearest hundredth, is the area of the training wheel than the area of the regular bicycle wheel?
a 21.98
b 153.86
285.74
d 1,142.96

Answer 1

To find the area of a circle, you use the formula A = πr^2, where A is the area and r is the radius.

For the training wheel with a radius of 3 inches:
A_training = π(3^2) = 9π square inches

For the regular bicycle wheel with a radius of 10 inches:
A_regular = π(10^2) = 100π square inches

Now, we can find the difference in area:
Difference = A_regular - A_training
Difference = 100π - 9π
Difference = 91π
Difference ≈ 285.74 square inches

Therefore, the correct answer is c) 285.74