First focus on the area ABOVE the dotted line. The shape here is that of a trapezoid. The two leg lengths are 12 in and 18 in (18 in is the diameter). At the far right of this trapezoid we can picture a triangle of base 3 in, height h and hypotenuse 5 in. Using the Pythagorean Theorem, we get h = 4 in.
This 4 in measurement is the width of the trapezoid. Thus, we are now ready to apply the formula for the area of a trapezoid: A = (average length of legs)*(width).
Here that area comes out to
12 in + 18 in
A = --------------------- * 4 in = 15 in*4in = 60 in^2, or (to the nearest hundredth)
The graph starts at the origin so there won't be a y intercept and the slope its 8 because every book costs 8 dollars. Therefore, the equation will be y=8x. Hope this helped
