The perimeter of a trapezoid is 50 and the sum of the non-parallel sides is 20. Find the midline of the trapezoid.

Since, by condition, the sum of the sides is 20 cm, then AB + CD = 20 cm.

The perimeter of the trapezoid is: Ravsd = (AB + CD) + BC + AD, then:

(BC + AD) = Ravsd – (AB + CD) = 50 – 20 = 30 cm.

The middle line of the trapezoid is: KM = (BC + AD) / 2 = 30/2 = 15 cm.

Answer: The length of the middle line is 15 cm.




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