In order fo find the area of the irregular figure, let's make it regular by drawing the blue square
Notice The red lined is 18 m, since 42-24=18
Thus the area of that square (call it x) is 18*18=324 m^2
Now let's find the area of the whole shape (Including the blue square) It is a rectangle with length of 42 and width of 12+18=30
Thus the area of the rectangle is length*width=42*30=1260
Since we want the area of the irregular shape without the blue square, 1260-324=936 m^2
