Question

please help me this questions

Answer 1

by Pythagoras in triangle OAB find the value of AB which is 5 and then we see that this follow the Pythagoras theorem so by cnvrse of Pythagoras theorem angle OAB is 90

Answer 2

In OAB, AB is not given...
So find AB by Pythagoras theorm...
OA²+OB²=AB²...
Then in bigger triangle do Pythagoras theorm,
by showing LHS =RHS
It will come equal and this will prove that angle CAB =90 degree.....