1. **State the problem:**
We are given a pyramid with base edge length $5$ ft and slant height $13$ ft. We need to find the lateral area, surface area, and volume.
2. **Identify given values and variables:**
- Perimeter of base, $P = 2$ (given, but this seems inconsistent with base edge 5 ft; we will calculate $P$ based on base edge)
- Slant height, $l = 3$ (given, but the image shows slant height $13$ ft; we will use $l=13$ ft as per the label)
- Base edge length = $5$ ft
- Base area, $B = ?$
- Apothem, $a = ?$
3. **Calculate perimeter $P$ of the base:**
Assuming the base is a square (common for pyramids), perimeter is
$$P = 4 \times 5 = 20$$
4. **Calculate base area $B$:**
For a square base,
$$B = 5 \times 5 = 25$$
5. **Calculate lateral area:**
Formula for lateral area of a pyramid:
$$\text{Lateral Area} = \frac{1}{2} P l$$
Substitute values:
$$= \frac{1}{2} \times 20 \times 13 = 10 \times 13 = 130$$
6. **Calculate surface area:**
Surface area is lateral area plus base area:
$$\text{Surface Area} = \text{Lateral Area} + B = 130 + 25 = 155$$
7. **Calculate volume:**
Volume formula for pyramid:
$$V = \frac{1}{3} B h$$
We need height $h$, not slant height. Use Pythagoras theorem in the triangle formed by height, apothem, and slant height.
Calculate apothem $a$ (distance from center to midpoint of base edge):
$$a = \frac{5}{2} = 2.5$$
Use Pythagoras theorem:
$$l^2 = h^2 + a^2$$
$$13^2 = h^2 + 2.5^2$$
$$169 = h^2 + 6.25$$
$$h^2 = 169 - 6.25 = 162.75$$
$$h = \sqrt{162.75} \approx 12.76$$
Calculate volume:
$$V = \frac{1}{3} \times 25 \times 12.76 = \frac{25 \times 12.76}{3} = \frac{319}{3} \approx 106.33$$
**Final answers:**
- Lateral Area = 130
- Surface Area = 155
- Volume = 106.33
Pyramid Area Volume 20853D
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