Final answer:
To find the other parallel side of the trapezium, use the formula A = 1/2 × (a + b) × h and substitute the given values. Solve for x to find the other parallel side.
Step-by-step explanation:
To find the area of a trapezium, you can use the formula A = 1/2 × (a + b) × h, where a and b are the lengths of the parallel sides and h is the height.
In this case, the height is given as 3 cm and one of the parallel sides is 9 cm. Let's call the other parallel side x.
Using the formula, we can substitute the given values:
A = 1/2 × (9 + x) × 3
Since the area of the trapezium is given as 24 cm², we can now solve for x:
24 = 1/2 × (9 + x) × 3
48 = (9 + x) × 3
48 = 27 + 3x
3x = 48 - 27
3x = 21
x = 21/3
x = 7
Therefore, the other parallel side of the trapezium is 7 cm.