What is the length of each side of the square that had the same area as a rectangle that has a length of 16 ft and a width 12.25 ft

area of rectangle = 16 x 12.25 = 196 square feet

 area of a square is S^2

196=s^2

s=sqrt(196) = 14

length os side for square is 14 feet

Your answer is B. 

Triangles: 
no sides the same: scalene 
2 sides the same: isosceles 
all (3) sides the same: equilateral 

Since a triangle's angles must add up to 180, if there are 2 45 degree angles, the one left must 90 degrees. Do you know what a triangle is called if it has a 90 degree angle?