Answer :
A trapezoid is a polygon of four sides with two parallel sides.
The area of trapezoid is the half sum of the lengths of the paralled sides times the height which is the distance between the parallel sides.
Call b1 and b2 the lengths of the two parallel sides and H the heigth, the formula is [1/2](b1 + b2) H.
We know b1 = 12cm, b2 = 12cm + 2 cm, and the area = 39 cm^2, then we can find H:
39 = [1/2](12 + 14)*H
39 = (13/2)H => H = 2*39 / 13 = 6 cm
Answer: 6 cm
The area of trapezoid is the half sum of the lengths of the paralled sides times the height which is the distance between the parallel sides.
Call b1 and b2 the lengths of the two parallel sides and H the heigth, the formula is [1/2](b1 + b2) H.
We know b1 = 12cm, b2 = 12cm + 2 cm, and the area = 39 cm^2, then we can find H:
39 = [1/2](12 + 14)*H
39 = (13/2)H => H = 2*39 / 13 = 6 cm
Answer: 6 cm