Answer:
Increase in area of circle is [tex]263.76[/tex] square mm
Step-by-step explanation:
The actual question is
Find the approximate increase in its area if the radius increases from 20 mm to 22 mm.
Solution
The area of a circle of radius r is given by
[tex]A = \pi r^2[/tex]
Area of circle of radius 20 mm is
[tex]A_1 = \pi 20^2\\A_1 = 400\pi[/tex] square mm
Area of circle of radius 22 mm is
[tex]A_2 = \pi 22^2\\A_2 = 484\pi[/tex] square mm
Increase in area of circle
[tex]A_2 - A_1 = 484 \pi - 400 \pi \\A_2 - A_1 = 84 \pi \\A_2 - A_1 = 263.76[/tex] square mm
