Answer: 127.795 in^2
Step-by-step explanation:
The area of any triangle is [tex]\frac{1}{2} \cdot \text{base} \cdot \text{height}[/tex][tex]\frac{1}{2} \cdot \text{base} \cdot \text{height}[/tex]
The surface of this pyramid is composed of three slanted triangles and the base.
Area of slanted sides (3 of them):
The base of each is 6.1 -- the sides of the bottom triangle all have the same length. The height of a slanted side is 12.2 .
Area of one slanted side is .5(6.1)(12.2) = 37.21
There are 3 identical sides, so the area of all 3 is 3 x 37.21 = 111.63 .
Area of the pyramid's base:
The base of that triangle is 6.1, and its height is 5.3, so its area is
.5(6.1)(5.3) = 16.165
The total area of all four faces is 111.63 + 16.165 = 127.795
