## Thursday, December 31, 2009

### Problem 411: Triangle, Median, Angles

Proposed Problem
Click the figure below to see the complete problem 411 about Triangle, Median, Angles.

Complete Problem 411
Level: High School, SAT Prep, College geometry

1. http://geometri-problemleri.blogspot.com/2009/12/problem-59-ve-cozumu.html

2. draw DE middle line of ABC

DE = X = 1/2 AC = 6

3. simular triangles x=6

4. x = 5.443

5. To Anonymous, March 23, 2010 5:14 AM

x = 5.443 (Not correct)

6. Hint : 51+51+78 = 180

7. I'm korean, i am interested in your math problems,,
i solved it that way : straight AC so DA parallel ED.. and triangle BEA is isosceles triangle,, finally 1:2=x:12 x=6 am i right?
i'm sorry i can't write english well,,

8. To Anonymous, problem #411: Your answer is right (I think that in your solution: DA is parallel to BE)

9. Problem 411
In extension of the CA to get A point E such that EA=AD=x ,so triangle BAD= triangle BAE(<EAB=<BAD=51) then BE=BD and <EBA=<ABC, so BE/BC=EA/AC or ½=x/12
Therefore x=6.