A) $ 6cm $
B) $ 10cm $
C) $ 12cm $
D) $ 18cm $
Correct Answer: C
$ \therefore $ $ AQ=AR $ (i) $ BP=BQ $ (ii) and $ CP=CR $ … (iii) Now. perimeter of $ \Delta ABC=AB+BC+AC $ $ =AB+BP+CP+AC $ Here, $ BQ=BP $ and $ CP=CR $ $ =AB+BQ+CR+AC $ [using Eqs. (ii) and (iii)] $ AB+BQ=AQ $ … (iv) $ AC+CR=AR $ … (v) Now, adding Eqs. (iv) and (v) $ AB+BQ+AC+CR=AQ+AR $ [Now, AQ = AR]
$ \Rightarrow $ $ AB+BQ+AC+CR=2AQ $ $ =2\times 6=12 $ Now, perimeter of $ \Delta ABC=2\times 6=12 $