W celu wyznaczenia wysokości h i odcinka x korzystamy z twierdzenia Pitagorasa.
[tex]h^{2}+3^{2} = 5^{2}\\\\h^{2}+9 = 25\\\\h^{2} = 25 - 9\\\\h^{2} = 16\\\\h = \sqrt{16}\\\\h = 4\\\\\\x^{2}+h^{2} = (4\sqrt{5})^{2}\\\\x^{2}+16= 80\\\\x^{2} = 80-16\\\\x^{2} = 64\\\\x = \sqrt{64}\\\\x = 8\\\\\\a = 3+x = 3+8 = 11\\h = 4\\\\\\P = \frac{1}{2}ah\\\\P = \frac{1}{2}\cdot11\cdot4 = 11\cdot2 = 22 \ \ [j^{2}][/tex]
