If d₁ and d₂ are the lengths of the diagonals, the area is given by .. A = (1/2)*d₁*d₂ .. A = (1/2)*(12 in)*(16 in) .. A = 96 in²
If b is the base and h is the height, the area is given by .. A = b*h We know the values of A and b, so .. 96 in² = (10 in)*h .. (96 in²)/(10 in) = h = 9.6 in