Answer: 42.9
There are two triangles: triangle MAB and triangle MNP
The slanted sides on the right side of the triangles are MB and MP. They correspond to one another. So they form a ratio MB/MP. I have the smaller piece up top. So we'll have the smaller piece of MAB's other known side which is MA = 35.2 (subtract 67.22 and 32) and we'll divide MA over MN = 67.2 making the ratio MA/MN
Solve the proportion for x
MB/MP = MA/MN
x/81.9 = 35.2/67.2
67.2*x = 81.9*35.2 <<--- cross multiply
67.2*x = 2882.88
x = 2882.88/67.2 <<--- divide both sides by 67.2
x = 42.9