Find equation for question number 4 , 5 and 6

Prism m and pyramid n have the same base area and the same height. cylinder p and prism q have the same height and the same base perimeter. cone z has the same base area as cylinder y, but its height is three times the height of cylinder y. the figures and have the same volume.

To decrease an amount by 16% what single multiplier would you use

Find y to the nearest hundreds place