Really need help for this cliff question

Question

A man stood on top of a cliff, MN, at 50m high. He observed two ships, A and B such that the distance MA=120m and MB=150m respectively. Calculate the distance between the two ships

(the cliff is a right Angled triangle with point M at the top, point N is at the bottom left and B is at the bottom right. Point A is in between point N and B)

*Please show me the full workings and answers. Thank you. *

Answer 1

MB² = MN² + NB²

 

You substitute the values and determine NB

 

MA² = MN² + NA²

 

You substitute the values and determine NA

 

AB = NB - NA