split the shape up
4 equal triagles
1 square
area of triangle=1/2bh
area of square=side^2
area of 1 triangle=1/2(m)n
area of 1 triangle=1/2(15)12
area=90
times 4 since 4 triangle
90*4=360
area of square
side=m=12
area=12^2=144
total area=square+triangles
total area=360+144=504
answer is B
