7th Grade Math
posted by Anonymous .
What is the radius of a CD in cm? What\'s the height of a CD cm? What\'s the volume of the CD? What\'s the measure of the radius in the center of the CD to the beginning of the music area and the volume of it? Subtract the answer from Part D from your answer in Part C and find the volume used for the music. How many minutes of music are on the CD? How many minutes are stored in each cubic centimeters of the volume?

Two rectangles are similar the ratio of the lengths of their corresponding sides is 1:2 find the ratio of peremiters of the rectangles then find the ratio of areas

It's really straight forward. You measure the radius (distance from the center of the CD to the outside) and the height (measure the thickness of the CD) then you find the area of the CD's surface by multiplying the radius by itself then multiplying your answer times 3.14 or pi (a= (pi)r^2) then when you've found that you multiply it by the height of the CD and you've found the volume. To find how many minutes of music there are you simply find the length of all the music on the CD and you divide that by the volume of the CD.