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 m
• B. 50 m
• C. 20 m
• D. 25 m

Answer 1

The correct option is D 25 m

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

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

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

Diameter of the outer circle = 90 m
Radius of the outer circle = $\frac{90}{2}$
= 45 m

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 m - 20 m
= 25 m

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