There is a triangle embedded in triangle MNO, which is triangle PQO, and these are similar triangles in that their corresponding sides are always in the same ratio, which in this case is 2:1, as MP = MO due to the midpoint definition, and therefore MO is twice as long as MP. Same for NO and QO.
Now that we know the ratio, we can set 6x-4 = 2(-5x+64)
