c) The 2 triangles are similar , then we can write:
5x/45 = 20/36 . Cross multiplication:
5x*36 = 45*20
180x = 900 and x = 900/180 , x = 5 (and 5x = 25)
d) Remember the proportionality theorem (or Thales')
You can write the following proportion:
GH/HJ = KL/LM
8/6 = 10/x . Cross multiplication:
8x = 60 and x = 60/8 , x = 7.5