In the trapezoid ABCD AD = 5, AD is 2.5 times more than BC. Find the midline of the trapezoid.

A trapezoid is a quadrilateral in which only two sides lie on parallel lines, and the sides are not equal to each other.

The middle line is a segment that runs parallel to the bases of the trapezoid and connects the midpoints of the sides. It is equal to half the sum of the bases of this trapezoid:

m = (BC + AD) / 2.

Since the larger base AD is 5 cm, and the length of the smaller base BC is two and a half times less than the length AD, then:

BC = AD / 2.5;

BC = 5 / 2.5 = 2 cm.

Now let’s find the middle line:

m = (5 + 2) / 2 = 7/2 = 3.5 cm.

Answer: The middle line of the trapezoid is 3.5 cm.