The middle line of the trapezoid is 9 cm, and one of the bases is 4 m larger than the other. Find the base of the trapezoid.

The midline of the trapezoid is the line segment that connects the midpoints of the sides. It is parallel to the bases and equal to their half-sum:

m = (a + b) / 2;

Since the base of AD is 4 m larger than the base of the BC, then we express:

x – base of the aircraft;

x + 4 – base AD;

(x + x + 4) / 2 = 9;

x + x + 4 = 9 2;

x + x + 4 = 18;

x + x = 18 – 4;

2x = 14;

x = 14/2 = 7;

BC = 7 m;

AD = 7 + 4 = 11 m.

Answer: the bases of the trapezoid are 7 m and 11 m.