1. **State the problem:** We have a composite shape made of a triangle on top of a trapezium. The area of the triangle is given as 28 cm². The triangle's height is 7 cm, and the trapezium's height is 2 cm. The trapezium has a base of 5 cm. We need to find the area of the trapezium.
2. **Recall the formula for the area of a triangle:**
$$\text{Area} = \frac{1}{2} \times \text{base} \times \text{height}$$
3. **Find the base of the triangle:**
Given the area of the triangle is 28 cm² and height is 7 cm, substitute into the formula:
$$28 = \frac{1}{2} \times \text{base} \times 7$$
4. **Solve for the base:**
Multiply both sides by 2:
$$2 \times 28 = \cancel{2} \times \frac{1}{\cancel{2}} \times \text{base} \times 7$$
$$56 = \text{base} \times 7$$
Divide both sides by 7:
$$\frac{56}{\cancel{7}} = \text{base} \times \frac{\cancel{7}}{7}$$
$$8 = \text{base}$$
So, the base of the triangle is 8 cm.
5. **Understand the trapezium dimensions:**
The trapezium shares the same top base as the triangle's base, which is 8 cm, and has a bottom base of 5 cm. Its height is 2 cm.
6. **Recall the formula for the area of a trapezium:**
$$\text{Area} = \frac{1}{2} \times (\text{sum of parallel sides}) \times \text{height}$$
7. **Calculate the area of the trapezium:**
$$\text{Area} = \frac{1}{2} \times (8 + 5) \times 2$$
$$= \frac{1}{2} \times 13 \times 2$$
8. **Simplify:**
$$= \cancel{\frac{1}{2}} \times 13 \times \cancel{2}$$
$$= 13$$
**Final answer:** The area of the trapezium is 13 cm².
Area Trapezium B7A7Ed
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