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SAT Math 2.5 Geometry and Measurement 258 Views


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SAT Math 2.5 Geometry and Measurement


Transcript

00:02

Here’s your shmoop du jour, brought to you by isosceles triangles. I came, I saw, I sosceles.

00:11

Triangle ACD is an isosceles triangle, and CD is parallel to BE.

00:16

What is the perimeter of triangle ABE?

00:20

Here are the potential answers...

00:24

Okay, so times are hard, and there’s a mad cheese shortage.

00:27

So…we have to leave out a smaller hunk of cheese to catch that mouse who’s been running

00:31

around our office like he owns the place…

00:33

Okay, our cheese triangle needs a downgrade. Now… because we’re told that CD is parallel

00:37

to BE, we know that triangles ABE and ACD are similar.

00:42

We’re also told that ACD is an isosceles triangle… and because all similar triangles

00:47

maintain the same proportions, we know that ABE is isosceles as well.

00:52

And THAT means that sides AD and AC are equal.

00:58

We can subtract the 6 they give us from 16 to get a side length

01:01

for AB of 10… which is also the length of AE.

01:06

And it’s mere addition from here to get our perimeter… 10 plus 10 plus 8 is 28…

01:10

…Answer is B. As in “brie.”

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