A = 64
A = bh/2
Now let's modify this formula that the base is 2 times the height.
64 = 2x(x) / 2
64 = 2x^2 / 2
64 = x^2
8 = x
Therefore the length of the height is 8
Proof:
2x = 2(8) = 16
x = 8
16 (base) is twice as much times as 8 (height)
A = bh/2
A = 16(8) / 2
A = 128 / 2
A = 64