Answer:
108 cm²
Step-by-step explanation:
The formula for the lateral area of a pyramid such as this is ...
LA = 1/2Ps
where P is the perimeter of the base (6·3 cm = 18 cm) and s is the slant height (12 cm). Putting the given values into the formula gives ...
A = 1/2·(18 cm)·(12 cm) = 108 cm²
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The formula gives the total area of the 6 triangular faces. Each face has an area of ...
A = 1/2·b·h = (1/2)(3 cm)(12 cm) = 18 cm²
Then the total area of the six triangles is ...
6 · 18 cm² = 108 cm²
