Consider the bigger triangle as △ABC, such that, ∠ABC=90∘
AC=17, AB=8 and a line from A meets BC at D, BD=6
Now, In △ABC,
Using Pythagoras Theorem,
AB2+BC2=AC2
82+BC2=172
BC2=289−64
BC=15
Now, In △ABD,
Using Pythagoras Theorem,
AB2+BD2=AD2
82+62=AD2
AD2=100
AD=10
sinx∘=PH=ABAC=817