Calculate the area of a trapezium with parallel sides measuring 20 cm and 18 cm, and the height between these sides is 15 cm.

Explanation

The area of a trapezium is given by the formula: 1/2 × (sum of the lengths of the parallel sides) × height. Here, it is 1/2 × (20 + 18) × 15 = 285 square centimeters.