The distance between the parallel sides of a trapezium is 18 cm. If the area of the trapezium is 1188 cm², then what is the sum of the lengths of the parallel sides?

The correct answer is 132 cm.

To find the sum of the lengths of the parallel sides of a trapezium, we can use the formula for the area of a trapezium:
$\text{Area}=\frac{1}{2}\times \left(\text{Sum of the parallel sides}\right)\times \text{Distance between the parallel sides}$

Let the sum of the lengths of the parallel sides be $S$ cm. We are given the following values in the problem:
- Area of the trapezium = 1188 cm²
- Distance between the parallel sides (height) = 18 cm

Substituting these values into the area formula, we get:
$1188=\frac{1}{2}\times S\times 18$

Simplify the right side of the equation by dividing 18 by 2:
$1188=S\times 9$

Now, solve for $S$ by dividing both sides by 9:
$S=\frac{1188}{9}$
$S=132$

Therefore, the sum of the lengths of the parallel sides is 132 cm.