Sketch the nets of the following pyramids and hence work out the surface area of each. Pyramid (c) has a square base with side length 12 cm and slant edges of 10 cm.

        $$
        A_{base} = (12 \text{ cm})^2 = 144 \text{ cm}^2
        $$

        $$
        A_{triangle} = \frac{1}{2} \times \text{base} \times \text{height}_t = \frac{1}{2} \times 12 \text{ cm} \times 8 \text{ cm} = 48 \text{ cm}^2
        $$

        $$
        A_{lateral} = 4 \times 48 \text{ cm}^2 = 192 \text{ cm}^2
        $$

        $$
        A_{total} = A_{base} + A_{lateral} = 144 \text{ cm}^2 + 192 \text{ cm}^2 = 336 \text{ cm}^2
        $$
        The surface area is $\text{}336 \text{ cm}^2\text{}$