Question: A sign for an ice cream shop is made from a semicircle and an isosceles triangle, as shown below.
What is the total area of the sign?
Give your answer to 1 d.p.
48 cm
63 cm
Graph shape: A green semicircle sits on top of a brown isosceles triangle; the semicircle has diameter 48 cm (top-left to top-right), and the triangle shares the same 48 cm top base with its apex pointing downward.
1. **State the problem:** We need to find the total area of a sign composed of a semicircle on top of an isosceles triangle. The semicircle has a diameter of $48$ cm, and the triangle has a base of $48$ cm and a height of $63$ cm.
2. **Formulas used:**
- Area of a semicircle: $$A_{semi} = \frac{1}{2} \pi r^2$$ where $r$ is the radius.
- Area of a triangle: $$A_{triangle} = \frac{1}{2} \times base \times height$$
3. **Calculate the radius of the semicircle:**
$$r = \frac{diameter}{2} = \frac{48}{2} = 24 \text{ cm}$$
4. **Calculate the area of the semicircle:**
$$A_{semi} = \frac{1}{2} \pi (24)^2 = \frac{1}{2} \pi 576 = 288\pi$$
5. **Calculate the area of the triangle:**
$$A_{triangle} = \frac{1}{2} \times 48 \times 63 = 24 \times 63 = 1512$$
6. **Calculate the total area:**
$$A_{total} = A_{semi} + A_{triangle} = 288\pi + 1512$$
7. **Approximate the total area using $\pi \approx 3.1416$:**
$$288 \times 3.1416 = 904.78$$
$$A_{total} \approx 904.78 + 1512 = 2416.78$$
8. **Round to 1 decimal place:**
$$\boxed{2416.8 \text{ cm}^2}$$