Answer:
BC = 21 cm
Step-by-step explanation:
The formula for the area of a trapezoid is
[tex]A=\frac{a+b}{2} h[/tex]
So, if we know, a, h, and A, we can them solve for b
[tex]b=\frac{2A}{h} -a[/tex]
So plugging this into the formula, we get
[tex]b=\frac{2(503.25)}{18.3} - 34\\\\b=\frac{1006.5}{18.3} - 34\\\\b=55 - 34\\\\b=21[/tex]
