Question

PLEASE HELP!!!!!!!! ASAP

A circle has a radius of 5 inches. A semicircle has a radius of 10 inches. How do the areas compare?

1. The circle has twice the area of the semicircle.
2. The semicircle has four times the area of the circle.
3. The semicircle has twice the area of the circle.
4. The areas are equal.

Question #2
A circle has a diameter of 6 cm. What is its area?

1. 37.68 cm 2
2. 9.42 cm 2
3. 28.26 cm 2
4. 18.84 cm 2

Answer 1

Question 1: The areas are equal
Question 2: The area of the circle would be 28.26 cm 2

Answer 2

Answer: #1) 3. The semicircle has twice the area of the circle

#2) 3. 28.26 cm

Explanation:

#1) The formula for area of circle is A=πr².

First, plugging in the radius for the circle, A=π(5)², we get an area of about 78.54 inches².

Plugging in the radius for the semicircle, A=π(10)², which is equal to 314.159.... However, since it is a SEMI-circle, we will divide this value by 2 to give us an area of about 157.08 inches².

Comparing the two areas, we see the semicircle has twice the area of the circle as 78.54 x 2 = 157.08.

#2) Again use the area of circle formula, A=πr². The radius is half the diameter, so half of 6cm=3cm, meaning r=3. plug it in.

A= π(3)²

A= 28.27 cm²