Question 896837
length of the other base is 12.


area of a trapezoid is equal to 1/2 * h * (b1 + b2)


h = 18
b1 = 10
b2 = 12


area = 1/2 * 18 * (22) = 9 * 22 = 198


you solve by plugging what you know in the formula and then solving for what you don't know.


you know that area is 198 and height 18 and one of the bases is 10.


formula becomes:


198 = 1/2 * 18 * (b1 + 10)


simplify to get 198 = 9 * (b1 + 10)


divide both sides by 9 to get:


198/9 = b1 + 10


subtract 10 from both sides to get:


198/9 - 10 = b1


solve for b1 to get b1 = 12.