How do I find the area of a trapezium with parallel sides 8 cm and 12 cm?

The area of a trapezium is half the sum of the parallel sides multiplied by the height. The formula is Area = (1/2) × (a + b) × h, where a and b are the two parallel sides and h is the perpendicular height between them. Here a = 8 cm, b = 12 cm, and h = 5 cm. First add the parallel sides: 8 + 12 = 20. Then multiply by the height: 20 × 5 = 100. Finally take half: 100 ÷ 2 = 50. So the area is 50 square centimetres. Remember the height must be the perpendicular distance between the parallel sides, not a slanting side, and the answer is always in square units.