The area of rectangle ABCD with vertices A(0, 0), B(0, 4), C(x, 4) and D(x, 0) is 32 square units. If x > 0, what is the value of x?
ABCD is a rectangle, so that means AB is one of its sides. AB has length 4. That means the other side of the rectangle has length 32/4 = 8 units. That means the x coordinate of point C and point D has to be 8 units away from the origin.
Note: In the problem it says x > 0 so x cannot be -8.
Thus, x = 8.