Question

solve the question no3 b.i

Answer 1

oo it is what you say

Answer 2

according to me the angle mentioned theta isX

now taking that same going to solve...

in triangle ADC
by Pythagoras theoram

${ad}^{2} + {dc}^{2} = {ac}^{2} \\ {5}^{2} + {ad}^{2} = {13}^{2} \\ {ad}^{2} = 169 - 25 \\ ad = \sqrt{144 } \\ ad = 12$
now in triangle ABD
BD=21-5=16
use Pythagoras theoram again..
we get AB=20

SO SINX=12/20
SINX=3/5. ANS.