Question

A rectangular paperboard measuring 20in long and 12in wide has a semicircle cut out of it, as shown below. What is the perimeter of the paperboard that remains after the semicircle is removed? (Use the value 3.14 for pi , and do not round your answer. Be sure to include the correct unit in your answer.)

Answer 1

the perimeter of the paperboard that remains after the semicircle is removed is 82.84 inches.

Explanation:

The perimeter of the paperboard that remains after the semicircle is removed is equal to the sum of the four sides of the rectangular portion of the paperboard plus half the circumference of the semicircle.

The rectangle has dimensions of length = 20 inches and width = 12 inches. Therefore, the sum of the four sides of the rectangular portion of the paperboard is:

2(20) + 2(12) = 64 inches

The semicircle has a diameter equal to the width of the rectangle, which is 12 inches. Therefore, the radius of the semicircle is half the diameter, or 6 inches. The circumference of a full circle with a radius of 6 inches is:

2 * 3.14 * 6 = 37.68 inches

Half of the circumference of the semicircle is:

(1/2) * 37.68 = 18.84 inches

Therefore, the perimeter of the paperboard that remains after the semicircle is removed is:

64 + 18.84 = 82.84 inches

Thus, the perimeter of the paperboard that remains after the semicircle is removed is 82.84 inches.