Question

a trapezoid has one base of 10 inches,an altitude of 6 inches and an area of 51 square inches, find the length of the other base

Answer 1

$\bf \textit{area of a trapezoid}\\\\ A=\cfrac{h(a+b)}{2}~~ \begin{cases} a,b=\stackrel{bases}{parallel~sides}\\ h=height\\ ---------\\ a=10\\ h=6\\ A=51 \end{cases}\implies 51=\cfrac{6(10+b)}{2} \\\\\\ 51=3(10+b)\implies \cfrac{51}{3}=10+b\implies 17=10+b\implies 7=b$