In an isosceles trapezoid, the smaller base is equal to the lateral side.

In an isosceles trapezoid, the smaller base is equal to the lateral side. Find the area of the trapezoid if its perimeter is 26 cm, and the side is 5 cm.

Given: Trapezium;

BC = 5 cm;

AB = DC – isosceles;

BC = AB = DC = 5 cm;

Decision:

1. P = AB + BC + CD + AD;

26 = AD + 15;

AD = 11 cm;

2. S = (BC + AD) / 2 * BH;

3. AD = AH + HO + OD;

HO = 5 cm, AH = OD;

AH = (11 – 5) / 2 = 3 cm;

4. Consider. treug. ABH.

ABH – Egyptian, BH = 4 cm.

5.S = (5 + 11) / 2 * 4 = 32 cm sq.

Answer: 32 cm sq.