Triangle - computing angles

Posted on 2016-10-14
Last Modified: 2016-10-17
Dear experts I need help on the attached geometric (Triangle) Figure

The figure, given alongside, shows a triangle ABC whose sides AB and AC are produced upto D a nd E respectively. The bisectors of exterior angles so formed intersect each other at point I. If Ang BAC = 80d and Ang ACB = 50d, find:
1.      Ang ECB
2.      Ang DBC
3.      Ang ICB
4.      Ang IBC
5.      Ang BIC

Kindly let me know if any theorem is available which explains the geometric properties of this triangle.
Ang  =Angle
Question by:Excellearner
LVL 31

Accepted Solution

Paul Sauvé earned 500 total points
ID: 41843658
1-sum of the angles of a triangle = 180° = ACB+CAB+ABC
2-two angles are supplementary if the sum of their angles equals 180° = ACB + ECB = ABC+DBC
3-the bisectors of an angle divides the angle int 2 equal parts

this is sufficient information to solve for angles ECB, DBC, ICB, IBC and BIC

Author Comment

ID: 41845564
Dear experts,

I have worked the problems ‘myself’ without any help from anyone.
Please accept my apologies that I had to seek your help on some simple problems. Originally when I first tried to solve these questions, I panicked when I could not work the angles. It was then I posted the questions in Experts Exchange.
Today morning I woke up early 4 am (India time) and I sat down to work the angles myself. Surprisingly, I could work the angles.
I am attaching my workings for your review. All writings in ‘red’ ink is to show how I improvised the triangle to help resolve the angle.
Kindly let me know if you think if I have not understood correctly.
Also I will appreciate if someone can provide me a link where there are more tough diagrams shown which will enhance my understanding.
I am preparing for GMAT and I am self-learning Math topics. My subjects in college or A levels (Class Xi and XII) did not include Math and hence this struggle.
I have seen a few posts which are very encouraging and considerate in its response while considering that my ask in this forum may be too much (and not in line with the EE Policy). Having said that I have taken note of all the responses.

Thank you

Featured Post

Do You Know the 4 Main Threat Actor Types?

Do you know the main threat actor types? Most attackers fall into one of four categories, each with their own favored tactics, techniques, and procedures.

Join & Write a Comment

Suggested Solutions

Title # Comments Views Activity
Baseline sigma 8 26
Python tuple index error 4 64
Locating peaks of a graph in Excel 9 51
Rounding Values 11 49
Introduction On a scale of 1 to 10, how would you rate our Product? Many of us have answered that question time and time again. But only a few of us have had the pleasure of receiving a stack of the filled out surveys and being asked to do somethi…
Foreword (May 2015) This web page has appeared at Google.  It's definitely worth considering! How to Know You are Making a Difference at EE In August, 2013, one …
Illustrator's Shape Builder tool will let you combine shapes visually and interactively. This video shows the Mac version, but the tool works the same way in Windows. To follow along with this video, you can draw your own shapes or download the file…
When you create an app prototype with Adobe XD, you can insert system screens -- sharing or Control Center, for example -- with just a few clicks. This video shows you how. You can take the full course on Experts Exchange at

707 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question

Need Help in Real-Time?

Connect with top rated Experts

18 Experts available now in Live!

Get 1:1 Help Now