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# isosceles trapezoid

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A isosceles trapezoid has bases $$AB=15$$ and $$CD=20$$. Points $$E$$ and $$F$$ are on $$AD$$ and $$BC$$ respectively such that $$EF\parallel AB$$. If $$AE:ED=2:3$$, compute $$EF$$.

Dec 31, 2020

#1
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EF = 2(2*sin30º) + 15 = 17

Dec 31, 2020
#2
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Where did you get 30 degrees from?

Melody  Jan 1, 2021
#3
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Here is my take.

I have added a couple of points.

$$\frac{TE}{2x}=\frac{2.5}{5x}\\ TE=1\\ FE=1+15+1=17 units$$

Jan 1, 2021
#4
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A quicker way to look at it is that the difference between 15 and 20 is 5.

EF is 2/5 of the way from the short side.

2/5 of 5 = 2

so the length of EF will be 15+2 =17 units

Jan 1, 2021