Question

Help me plz for this sum plz plz

Answer 1

we know that a+b+c=180°

so B+C=180-A

orB/2 +C+C/2 = 90-(A/2)......(i)

now think in triangle BOC

we have three angle,OBC,BOC,OCB

OBC=(B/2)

OCB=(C/2)

Let BOC=X

so,x+(B/2)+(c/2)=180°

from equation...(i)

x+90°-A/2

x=90°+A/2

Hence prooved