Step-by-step explanation:
the side lengths of the base (the ground triangle) are equal. that means every ground side length is 8 in.
and that also makes the 3 triangles of the side areas of the pyramid equal.
so, for the surface area of the pyramid we need to calculate the area of one side area triangle, multiply it by 3 (as we have 3 side areas) and add the area of the ground triangle.
the area of a triangle is
baseline × height / 2
so, for a side area triangle we get
8 × 14 / 2 = 8×7 = 56 in²
all 3 side areas together are then
3×56 = 168 in²
the ground area triangle is then
8 × 6.9 / 2 = 4 × 6.9 = 27.6 in²
so, the total surface area of the pyramid is
168 + 27.6 = 195.6 in²
