Well, an area and perimeter have formula's. The formula of area is length times width. The formula of perimeter is to basically length plus length plus width plus width. For instance, let's say the rectangles width is 5 and length is 6. So you do 5 plus 5 which is 10 and then 6 plus 6 which is 12. And then, 12 plus 10 equals 22. So the perimeter would be 22. If you were to find the area, you would do 6 times 5 and the area would be 30.
I hope this helps :)
17 tens can be said as 17 x 10
So 17 x 10 is 170
170 is in standard form
To get the answer you divide the cds by 2 because the CD's are 1/2 in thick to get: 26 in
