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Proposed ProblemClick the figure below to see the complete problem 411 about Triangle, Median, Angles.See also:Complete Problem 411Level: High School, SAT Prep, College geometry
draw DE middle line of ABCDE = X = 1/2 AC = 6
simular triangles x=6
x = 5.443
To Anonymous, March 23, 2010 5:14 AMx = 5.443 (Not correct)
Hint : 51+51+78 = 180
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,,
To Anonymous, problem #411: Your answer is right (I think that in your solution: DA is parallel to BE)
Problem 411In 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/12Therefore x=6.