Geometry Problem. Post your solution in the comments box below.

Level: Mathematics Education, High School, Honors Geometry, College.

Click the figure below to view the complete problem 992

## Tuesday, March 11, 2014

### Geometry Problem 992: Triangle, Interior Point, Angles, 20, 30 , 40, 50 Degree

Labels:
20,
30 degrees,
40 degrees,
50,
angle,
triangle

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http://s25.postimg.org/7jzp7p7zz/Pro_992.png

ReplyDeleteDraw altitude CE of isosceles triangle ABC

We haves angles as shown on the sketch

D is the center of incircle of triangle AFC => angle DCF=10

So x= 180-60-10= 110

nice solution....

DeleteIf E is the circumcenter of tr. ABD, then tr. ADE is equilateral (1) and, easily, tr. ACE and BEC are isosceles; with (1) CD is bisector of <ACE, making <BCD=30,hence <BDC=110.

ReplyDeleteBest regards

Excellent Stan!

ReplyDelete