1. ## congruent triangles

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2. ## Re: congruent triangles

Originally Posted by kastamonu
View image: yenikelebek

use the tangent property of a right triangle to find the unknown angle

3. ## Re: congruent triangles

How?Which line do I have to draw?

4. ## Re: congruent triangles

Originally Posted by kastamonu
View image: yenikelebek
Are you very very sure that you have given us all the relevant information.
Have you stated the actual problem is its exact wording?
I think that you have put us down into the middle of a proof.

5. ## Re: congruent triangles

There is sufficient information to solve this problem. Answer is 63.4 degrees

6. ## Re: congruent triangles

Yes I did. It has something to do with congruent triangles. We have to draw a line.

7. ## Re: congruent triangles

Maybe we have to create an isosceles triangle. Angle is 40 degrees.

8. ## Re: congruent triangles

Originally Posted by kastamonu
Yes I did. It has something to do with congruent triangles. We have to draw a line.
Please give us the actual problem in its exact wording.

9. ## Re: congruent triangles

It is in Turkish.

10. ## Re: congruent triangles

I translated it word by word. I also sent a mail to the author.

11. ## Re: congruent triangles

View image: kelebek2 here it is.

12. ## Re: congruent triangles

My answer was based on angle ABE of 30 deg.If it is 40 deg I do not see a solution with out further info

13. ## Re: congruent triangles

In further review I have come up with 79.3 degrees for the unknown angle When I drew a diagram I found that CD was very close to a side of the equilateral triangle and decided that the angle could be calculated
1 find the length of AE using 8 as a side of equilateral .Altitude of AEC and segments on AC calculate using angles of 20 and60
3 Drop a perpendicular from D to AC extended.Mark F the intersection of same with AC ext
4 Angle DCF calculates fromDF and CF as 40.7
5 180-40.7-60= unknown =79.3

14. ## Re: congruent triangles

in post 13 line number2 should read AD=AE +ED.Triangle ADF is a 20-70 rt triangle so length of DF and AF can be calculated from AD.CF is AF-8

15. ## Re: congruent triangles

An swer is 80.But this is not a tri. question.If we can prove that CDE is isosceles....

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