Respuesta :

a)   The larger and small triangles are similar, so

8/10 =  x/15
x =  (8*15)/10 =  12 

b)find the altitude x
tan 40 = x / 5
x = 5 tan 40 = 4.195


By Pythagoras theorem:-

y =  sqrt ( 4.195^2 + 11^2)

y =  11.8  to 3 significant figures