Question

Fig. 8.66
8. In Fig. 8.67, is the centre of the circular and
ABC. Find the angles of A4BC
B
309
A
Fig. 8.67​

Answer 1

Answer:

Angle ABC=145 degree

Step-by-step explanation:

In triangle AOC,

OA=OC(radii)

Therefore, OCA=OAC

OCA+OAC+AOC=180

OCA=55= OAC

In triangle OAB,

OA=OB(radii)

Therefore,OBA=OAB

AOB+OBA+OAB=180(angle sum property)

OBA=70

OAB=AOC+CAB

CAB=15

In triangle OCB,

OC=OB

Therefore,OCB=OBC

OCB+OBC+BOC=180

OBC=75=OCB

OCB=OCA+ACB

ACB=20

ABC=ABO+CBO=145