[tex] {h}^{2} = {a}^{2} - ( \frac{1}{2} a)^{2} \\ {h}^{2} = a^{2} - \frac{1}{4} {a}^{2} \\ {h}^{2} = \frac{3}{4} {a}^{2} \\ h = \sqrt{ \frac{3}{4} {a}^{2} } \\ h = \frac{ \sqrt{3}a }{2} \\ h = \frac{a \sqrt{3} }{2} [/tex]
[tex]P = \frac{ah}{2} \\ P = \frac{a \times \frac{a \sqrt{3} }{2} }{2} \\ P = \frac{ \frac{a^{2} \sqrt{3} }{2} }{2} \\ P = \frac{ {a}^{2} \sqrt{ 3} }{2} \times \frac{1}{2} \\ P = \frac{ {a}^{2} \sqrt{3} }{4} [/tex]
