The area of a trapezoid is given by:
[tex]A=\frac{1}{2}(b_1+b_2)h[/tex]
where b1 and b2 are the bases of the trapezois and h is the height. In this case we have that A=198, b1=15 and h=12, plugging this values into the equation above and solving for b2 we have:
[tex]\begin{gathered} 198=\frac{1}{2}(b_2+15)12 \\ 2\cdot198=12(b_2+15) \\ 396=12(b_2+15) \\ \frac{396}{12}=b_2+15 \\ 33=b_2+15 \\ b_2=33-15 \\ b_2=18 \end{gathered}[/tex]
Therefore b2 is equal to 18 m
