Correct option is (b) 180 cm2
We divide the trapezium into 3 parts: 2 triangles and a rectangle.
Base of triangle = \(\frac{20 -10}2 = 5\)
Height of the triangle and rectangle (h)2 = 132 − 52
⇒ (h)2 = 144
⇒ h = 12
Area of trapezium = \(\frac 12\) × (sum of parallel sides) × (height)
= \(\frac 12\) × (10 + 20) × (12)
= 180 cm2