Question

Semi circle M has a radius of 15 inches. If an ant walks from A to B directly along diameter AB and a beetle walks from A to B around ACB, how much farther, to the nearest tenth of an inch, does the beetle walk?

Answer 1

Answer: The beetle walks 17.1 inches longer than the ant.

Explanation:

The radius of semicircle M is 15 inches, so its diameter (double the radius) is 30 inches.

The ant walks 30 inches.

The circumference of semicircle M is π multiplied by the diameter.

However, because M is a semicircle and not a circle, divide the circumference equation by 2 (because only half the circumference is there.)

The diameter is 30 inches.

`(30\pi )/(2)` = 47.1238898038

Rounded to the nearest tenth of an inch, the "circumference" of semicircle M is 47.1 inches.

47.1 - 30

The beetle walks 17.1 inches longer than the ant.