Question 963915

{{{A = (1/2)*h(b1+b2)

{{{140 = (1/2)*20(3+b)}}}

{{{140 = 10(3 +b)}}}.....just multiply right side

{{{140 = 30 +10b}}}

{{{140-30 =10b}}}

{{{110 =10b}}}

{{{110/10=b}}}

{{{b=11}}}