ABCD is a trapezium in which AB is parallel to CD, and E and F are the mid-points of non-parallel sides AD and BC. If EF is parallel to AB, AB = 28 cm and CD = 18 cm, then find EF (in cm).

Correct option is A

Given:
ABCD is a trapezium with AB $$\parallel$$​ CD
E and F are the midpoints of sides AD and BC

AB = 28 cm and  CD = 18 cm
EF is parallel to AB

Concept Used:
In a trapezium, the line joining the midpoints of the non-parallel sides (EF) is parallel to the parallel sides and its length is the average of the lengths of those sides.
Formula Used:
EF = $$\frac{AB + CD}{2}$$​​
Solution:
EF = $$\frac{28 + 18}{2} = \frac{46}{2} = 23$$ cm
Thus, the correct option is (a) 23