https://drive.google.com/file/d/10ICtLdBj8FfU8_OOiG0gC-JS8mfaFYZr/view?usp=drivesdk
Hint:
Let distance AB be x+3
Now work out an expression for the shaded region in terms of x and put it equal to 51
Solve for x
Now find the whole area.
+164 
