Answer:
6.1
Step-by-step explanation:
The area of a trapezoid is given by
A = 1/2 (b1+b2) * h where b1 and b2 are the lengths of the bases
108.6 = 1/2 ( 12+p) *12
108.6 = 6 (12+p)
Divide each side by 6
108.6 /6 = 12+p
18.1 = 12+p
Subtract 12 from each side
18.1-12 = 12+p-12
6.1 = p
