A geometry problem by sujoy roy

Geometry Level 4

ABC is an isosceles triangle with AB=AC and B A C = 4 0 \angle BAC=40^{\circ} . P is a point inside the triangle such that P B C = 3 0 \angle PBC=30^{\circ} and P C B = 5 0 \angle PCB=50^{\circ} . Find A P B \angle APB .

Note: Use only geometry to solve the problem.


The answer is 110.

This section requires Javascript.
You are seeing this because something didn't load right. We suggest you, (a) try refreshing the page, (b) enabling javascript if it is disabled on your browser and, finally, (c) loading the non-javascript version of this page . We're sorry about the hassle.

1 solution

Aaaaa Bbbbb
Jul 21, 2014

Denote: A H B C , A H × B P = I , B I H = C I H = 6 0 0 AH \perp BC, AH \times BP = I, \angle{BIH}=\angle{CIH}=60^{0} \Rightarrow IP is the bisector of angle AIC, beside PC is the bisector of angle ACI. P is the incenter of triangles ACI, AP is the bisector of the angle IAC. A P B = 18 0 0 ( 4 0 0 + 3 0 0 ) = 11 0 0 \Rightarrow \angle{APB}=180^{0}-(40^{0}+30^{0})=\boxed{110^{0}}

Need to explain properly. Not adequate information

Kaarthick Kumaran - 6 years, 10 months ago

What does the "x" between AH and BP indicate?

Perennial Nomad - 6 years, 10 months ago

Log in to reply

Point "I" is the intersection between AH and BP (AH x BP = I).

Enoc Cetina - 6 years, 10 months ago

well i did it with a lot of construction

akash deep - 6 years, 10 months ago

Using Lami's theorem, the value of angle APB comes to 169.709 degrees. Can somebody please check it?

Arnab Bhattacharya - 6 years, 10 months ago

Log in to reply

Can you show your working?

Calvin Lin Staff - 6 years, 6 months ago

0 pending reports

×

Problem Loading...

Note Loading...

Set Loading...