Hello Jack,
In this problem you've to use geometric mean (leg) theorem, which states that in a right triangle, the altitude from the right angle to the hypotenuse divides the hypotenuse into two segments.
The length of each leg of the right triangle is the geometric mean of the lengths of the hypotenuse and the segment of the hypotenuse that is adjacent to the leg.
AC2 = AP * AM and CM2 = MP * AM
AC2 : CM2 = (AP * AM) : (MP * AM) = AP : MP --------- (1)
Given AC : CM = 3 : 4
Therefore AC2 : CM2 = 32 : 42 = 9 : 16 = AP : MP ----------- BY (1) --------------(2)
AP = (9/16)*MP ------------ (3)
Given : MP - AP = 1-------------------(4)
MP - (9/16)*MP = 1 --------------- substitute value of AP from (3)
Solve for MP
MP = 16 / 7
Plug-in the value of MP in equation 4 and solve for AP.
AP = 9 /7
AM = AP + MP
= 9/7 + 16/7 = 25/7
Answer is AM = 25/7
I hope this helps. If you need further help myself or any other tutor can help.
Thank You,
Shefali J