Question

The diameter of this compact disc is 11.8cm. The hole in the middle has a area of 1.54cm2. What is the area of the plastic in this disc?

Answer 1

$A=A_{disc}-A_{hole}\\A=\pi r^2-(1.54)\\A=\pi(5.9)^2-1.54\\A=34.81\pi -1.54\\A=109.358840271-1.54\\A=107.818840271$

Area = 107.82 square inches.