A trapezium with area 100 cm² has parallel sides of 10 cm and 15 cm. What is the perpendicular distance between its parallel sides?

Given: Area of trapezium = 100 cm²

Two parallel sides are 10 cm and 15 cm.

Let d be the perpendicular distance between two parallel sides.

Area of trapezium = $\frac{1}{2}$ × (Sum of parallel sides) × (Distance between parallel sides)

⇒ 100 = $\frac{1}{2}$ × (10 + 15) × d

⇒ 200 = 25d

⇒ d = 8 cm

Therefore, the perpendicular distance between parallel sides is 8 cm.