In the figure, AC=10cm, PC= 15cm, PQ=12cm, find PB?
9cm
In △ABC and △PQC
∠PQC=∠ABC=90∘
∠C=∠C (common angle)
Therefore, △ABC∼△PQC by AA similarity
ACPC=ABPQ⇒1015=AB12⇒AB=8cm
In △ABC , by using Pythagoras theorem
AB2+BC2=AC2⇒BC=6cm
Now, PB = PC –BC = 15-6 = 9cm