Respuesta :

A = bh/2
40 = x(2x)/2
80 = 2x²
40 = x²
x = sqrt40
x = +/- 2sqrt10
Measurement cannot be negative therefore x = 2sqrt10
Height = 2x = 2(2sqrt10) = 4sqrt10
The height of the triangle is 4sqrt10 cm or approximately 12.65cm.