Question

ABCD is a rhombus such that ∠ACB = 40°. Then find the measure of∠ADB.

THERE IS NO DIAGRAM SO DON'T ASK FOR PIC

''AND IF YOU DON'T KNOW YOU NOT HAVE TO GIVE ANSWER OR YOU WILL BE REPORTED IMMEDIATELY AND ANSWER WILL DELETE''

Answer 1

Diagonals of a rhombus are perpendicular bisectors of each other and thus BOC is 90°.

In triangle boc, obc+ocb+cbo=180

obc=180-(40+90)

obc=180-130= 50°

Now, in triangles BOC and DOA,

boc=doa (vertically opp)

oa=oc (diagonals bisect each other)

bo=do (diagonals bisect each other)

Thus, triangle BOC is congruent to DOA by SAS congruency rule.

Thus, angle cbo=ado=50°

ADO is the same as ADB. Thus, ADB=50°