Need help with geometry

Question

asked Dec 19, 2020 152k views

1 Answer

Qihui · Answer 1 · 2020-12-26T02:08:08+0000

Answer:

The surface area is
$305.9\ ft^(2)$

Explanation:

we know that

The surface area of the square pyramid is equal to

SA=b^(2)+4[(1)/(2)bh]

where

b is the length side of the square base

h is the height of the lateral triangular face

we have

$b=10\ ft$

Applying Pythagoras Theorem find the value of h

h^(2)=9^(2)+(10/2)^(2)

h^(2)=81+25

$h=√(106)\ ft$

substitute in the formula

$SA=10^(2)+4[(1)/(2)(10)(√(106))]=305.9\ ft^(2)$