SOLUTION: length?

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Question 1011586: length?

Found 3 solutions by ikleyn, Freezie, Whiteboy:
Answer by ikleyn(53763) About Me  (Show Source):
You can put this solution on YOUR website!
.
length of EC?
AD= 11, BD = 3, BC = 12, AE = 9
http://imgur.com/Jh2lmZT
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Hello,

1) In your plot the point A is invisible, but I suspect it is upper vertex.
2) You didn't mention that the straight line DE is parallel to BC. 
   It is important part of the condition.

OK. Now, the triangles ABC and ADE are similar. It gives a proportion

abs%28AB%29%2Fabs%28AD%29 = abs%28AC%29%2Fabs%28AE%29,   or   %2811%2B3%29%2F11 = %289%2Bx%29%2F9,   or   14%2F11 = %289%2Bx%29%2F9

where x is an unknown length of EC.

Simplify and solve it for x.

14*9 = 11*(9+x)  ---->  126 = 99 + 11x  ----->  11x = 126-99 = 27  -----> x = 27%2F11.

The data BC = 12 is excessive for this problem.


Answer by Freezie(16) About Me  (Show Source):
Answer by Whiteboy(6) About Me  (Show Source):