The area of a trapezoid is $80$. The length of one base is $4$ units greater than the other base, and the height of the trapezoid is $12$. Find the perimeter of the trapezoid.
We set the smaller base to x, so the area of the trapezoid is
\(12x+24 = 80\)
\(12x = 56\)
\(x = \frac{19}{3}\)
Next, we find the diagonals by using pythagorean theorum.
a = 2
b = 12
c = \(\sqrt{148}\) = \(2\sqrt{39}\)
so the perimeter is 2x+4+2c = 38/3 + 4 + 4 root 39, or \(\frac{50}{3}+4\sqrt{39}\)