100%/x%=60/18
<span>(100/x)*x=(60/18)*x </span>
<span>100=3.33333333333*x </span>(3.33333333333)
<span>100/3.33333333333=x </span>
<span>30=x </span>
x=30
<span>now we have: </span>
<span>18 is 30% of 60</span>
The dimensions can vary. Here is a picture of a triangular prism with a right-triangle base.