Grade 7 - Mathematics 9.3 The Area of a Circular Path - I

Example:
The outer and inner radii of a ring are 65 cm. and 47.5 cm. Find the area of the ring (circular path).

Solution:
Given that,
R = 65 cm and r = 47.5 cm. The area of the ring = p(R+r)(R-r).
= 22/7 * (65 + 47.5) * (65 - 47.5)
= 22/7 * 112.5 * 17.5
= 43312.5 / 7
= 6187.5 sq cm.

Directions: Read the above example carefully and answer the following questions.

Draw 10 different rings and represent each with different color. Find the area of each of them.