Question

What is the difference between the inner radius and the outer radius, if the diameters of the two circles are given as shown in the figure?

• A. 35 yd
• B. 25 yd
• C. 20 yd
• D. 50 yd

Answer 1

The correct option is B 25 yd

Let's determine the radius of the outer and the inner circle first.

Radius = $\frac{Diameter}{2}$

Diameter of the inner circle = 40 yd
Radius of the inner circle = $\frac{40}{2}$
= 20 yd

Diameter of the outer circle = 90 yd
Radius of the outer circle = $\frac{90}{2}$
= 45 yd
To calculate the difference between both the two radii, we have to subtract the radius of inner circle from the radius of the outer circle.

Difference = 45 yd - 20 yd
= 25 yd

Hence, the difference between the outer radius and the inner radius is 25 yd.