Question 65177
Find the length of the other base of a trapezoid whose height is 16 metres, first base is 20, and whose area is 224 square metres.
Starting with the formula for the area of a trapezoid with bases, b1 and b2, and height,h:
{{{A = ((b1+b2)/2)h}}} where: h = 16m, b1 = 20m, and A = 224 sq.m, we'll solve for b2.

{{{224 = ((20+b2)/2)16}}} Divide both sides by 16.
{{{14 = (20+b2)/2}}} Multiply both sides by 2.
{{{28 = 20+b2}}} Subtract 20 from both sides.
{{{8 = b2}}}

The length of the other base is 8 metres.

Check:
{{{((20+8)/2)16 = (14)(16)}}} = {{{224}}}