Question 66

Circumference of two concentric circles are 176m and 132m. What is the different between their radii ?

Solution

Let radius of smaller circle = $$r_1$$ m

Radius of bigger circle = $$r_2$$ m

Circumference of smaller circle = $$2 \pi r_1 = 132$$

=> $$\pi r_1 = \frac{132}{2} = 66$$ ---------(i)

Similarly, $$\pi r_2 = \frac{176}{2} = 88$$ ------------(ii)

Subtracting eqn(i) from (ii), we get :

=> $$\pi (r_2 - r_1) = 88 - 66$$

=> $$r_2 - r_1 = 22 \times \frac{7}{22} = 7$$ m

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