Answer:
319
Explanation:
So, to find the surface area, first we find the base area, which is: 11 x 11 = 121
Then, we have to find the area of the other faces. Since each face is a triangle, we can use the formula A = 1/2 x b x h.
So,
b = 11
h = 9
1/2 x 11 x 9 = 49.5
The, we multiply by 4, the number of sides: 49.5 x 4 = 198
Then, we add the 2, values: 121 + 198,
Which gives us: 319.
Hope this helped!