SOLUTION: in ∆ABC ,AB=AC. Bisectors of ang. B and ang. c meet at O. If ang. A=40°,find the measure of ang. BOC. THANKYOU .

Algebra ->  Points-lines-and-rays -> SOLUTION: in ∆ABC ,AB=AC. Bisectors of ang. B and ang. c meet at O. If ang. A=40°,find the measure of ang. BOC. THANKYOU .       Log On


   



Question 1041488: in ∆ABC ,AB=AC. Bisectors of ang. B and ang. c meet at O. If ang. A=40°,find the measure of ang. BOC.
THANKYOU .

Answer by robertb(5830) About Me  (Show Source):
You can put this solution on YOUR website!
From the given AB = AC we know that the triangle is isosceles.
==> angle B is congruent to angle C
Since lines OB and OC bisect angles B and C respectively, angles ABO, OBC, ACO, and OCB are all congruent.
Let alpha be the measure of any one of these four angles.
==> 4%2Aalpha+%2B+40%5Eo+=+180%5Eo ==> alpha+=+35%5Eo .
==> Isoscles triangle BOC has base angles each measuring 35%5Eo.
==> Measure of angle BOC = 180%5Eo+-+2%2A35%5Eo+=+110%5Eo.