2. 90 rock CD's out of 125 CD's.

72%

Step-by-step explanation:

90/125 is .72

out of 125 CD's there are 72% of rock CD's and 28 of unknown CD's

The area of a rectangle can be calculated by the product of its length and the width. Here we are given the area and the length so we can simply calculate for width. The perimeter is the sum of all the side lengths of the shape. We calculate as follows:

Area = lxw
1/6 = 1.5w
w = 1/9

Perimeter = 2l + 2w
Perimeter = 5/9

Hope this answers the question. Have a nice day.