ProblemA=12(b1+b2)h, b1=3, b2=7, h=5A = \tfrac{1}{2}(b_1+b_2)h,\ b_1=3,\ b_2=7,\ h=5A=21(b1+b2)h, b1=3, b2=7, h=5Step-by-step solutionApply A=12(b1+b2)hA = \tfrac{1}{2}(b_1 + b_2) hA=21(b1+b2)h.Substitute: A=12(3+7)(5)=12(10)(5)=25A = \tfrac{1}{2}(3 + 7)(5) = \tfrac{1}{2}(10)(5) = 25A=21(3+7)(5)=21(10)(5)=25.AnswerA=25A = 25A=25Want to solve a different problem? Open the area solver →Related worked examples/solve/geometry/area-trapezoid-bases-5-8-height-4