In an equilateral trapezoid, the bases are 18 cm and 42 cm. The lateral side is 20 cm.

In an equilateral trapezoid, the bases are 18 cm and 42 cm. The lateral side is 20 cm. Calculate the height of the trapezoid and the midline of the trapezoid.

To find the height, find half the base difference:

1) (42 – 18) / 2 = 12 (cm).

Then the height will be a leg in a triangle with a hypotenuse equal to 20 cm, the second leg equal to 12 cm:

2) √202 – 122 = √400 – 144 = √256 = 16 (cm).

The middle line will be:

(18 + 42) / 2 = 30 (cm).

Answer: the height is 16 cm, the middle line is 30 cm.