Question 78111
Starting with the formula for the area of a trapezoid: {{{A = (1/2)(a+b)h}}} where: A = 224 sq.m., h = 16m., a = 20m, and b = x., you can write:
{{{(1/2)(20+x)(16) = 224}}} Simplifying this:
{{{8(20+x) = 224}}} Divide both sides by 8.
{{{20+x = 28}}} Subtract 20 from both sides.
{{{x = 8}}}m.
Check:
{{{(1/2)(20+8)(16) = (8)(28)}}} = 224