Aregular pyramid has a volume of 245 cubic inches. the regular pyramid has a height of 15 inches and a square base, how manu inches are in the length of one side of it's base

We know that
[volume of a square pyramid]=area of the base*height /3
area of the base=3*volume/height 
volume=245 in³
height=15 in
area of the base=3*245/15> 49 in²

the area of the base is a square
so
area=b²> b=√area> b=√49> b=7 in

the answer is
The length of one side is 7 in

Answer d; a supplementary angle = 180°, so if that angle = 150°, y would = 30°.

Provide an equation