From the basic knowledge of pythagoras thorem,
EH
X ^2 = 40^2 + 9^2 = 1`600 + 81 = 1681
X = square root of 1681
= ET = EH = X = 41 feet
NI
y ^ 2 = 9 ^2 + 9^2 = 81 + 81 = 162
y = square root of 162
NI = T I = y = 12.72 feet
The perimeter of the Kite = EN + ET + NI + TI = 41 + 41 + 12. 72 + 12. 72 = 107.44 feet