We know that the area of a rectangle is length * width, and the area of a triangle is 1/2 * base * height. However, we know that the areas are equal, or that
lw = 1/2bh
If we substitute in the measurements that we know, we can solve the following equation for x.
5x + 1 (x) = 1/2(8x)(x+1)
Let's simplify this equation by multiplying.
5x² + x = 4x² + 4x
Now, let's bring all of the variables to one side of the equation.
x² - 3x = 0
Finally, we should factor out the Greatest Common Factor.
x(x-3) = 0
Therefore, by the Zero Product Property, x = 0, 3. But since the measurement of the short side length of the rectangle is x, it cannot be zero. Thus, x = 3.
The question asks for the area of the rectangle, which is <span>5x² + x. </span> Let's solve this expression for x = 3.
5(3)² + 3 5(9) + 3 45 + 3 48
Therefore, the area of the rectangle is 48 square units, or option B.
