The area of a rectangular ice-skating rink is 900 square yards. if the length of the rink is 100 yards, want is the width of the rink? .

The width would be 90.

900/100=90

Since it give you the over all square yards, you take that number and divide it by what ever the number would be and that gives you the answer.

Well if you do the area divided by the length 
900/100 
You should get the length with would be 9 
Width=9 

What the heck don’t understand

Hello!
volume of sphere =4/3.pi.r^3