Answer:
Part 1) The slant height of the pyramid is 
Part 2) The length of the third side of the window is 
Part 3) The building's slant height is 
Step-by-step explanation:
Part 1) we know that
To find out the slant height of the pyramid, apply the Pythagorean Theorem
Let
l ----> the slant height of the pyramid
h ---> the height of the pyramid
b ---> the length side of the square base

we have

substitute the given values




Part 2) Let
c ----> the hypotenuse of a right triangle (the greater side)
a ---> the measure of one leg of the right triangle
b ---> the measure of the other leg of the right triangle
Applying the Pythagorean Theorem

we have

substitute the given values and solve for b




Part 3) Let
l ----> the building's slant height
h ---> the height of the building
r ---> the radius of the base of the building
Applying the Pythagorean Theorem

we have

substitute the given values


