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SAT Math 10.4 Geometry and Measurement 380 Views
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Description:
SAT Math 10.4 Geometry and Measurement. What is the perimeter of triangle DEF?
- Triangles / Similar Triangles
- Product Type / SAT Math
- Geometry / Similarity, right triangles, trigonometry, and dimensions
- Geometry / Understand similarity in terms of similarity transformations
- Similarity, Right Triangles, and Trigonometry / Understand similarity in terms of transformations
- Additional Topics in Math / Congruence and similarity
Transcript
- 00:02
Here’s your shmoop du jour, brought to you by similar triangles.
- 00:07
If it wasn’t for the tattoo, we wouldn’t be able to tell them apart.
- 00:10
Triangle ABC is similar to triangle DEF. What is the perimeter of triangle DEF?
- 00:18
Okay, we’ve got a couple of similar triangles here.
- 00:21
Apparently triangles of a feather flock together...
Full Transcript
- 00:24
All right, so these are both right triangles…
- 00:26
…and one of them has a leg with length 6 and a hypotenuse with length 10…
- 00:31
…Hello! Looks like we’ve got a 3-4-5 triangle...
- 00:35
Both known distances have been doubled from the original 3-4-5 ratio…
- 00:39
…so we know we have to double the missing length as well.
- 00:43
Four times two is eight… and we have a triangle with sides of 6, 8 and 10.
- 00:50
Plugging those numbers into our internal adding machine… we get a total perimeter of 24.
- 00:55
Now, before you waste gobs of time trying to figure out what the lengths of the sides in our other triangle are…
- 01:01
…just note that the one side we DO know is 2/3 of the corresponding side in triangle number one.
- 01:07
These triangles are similar… so the perimeter is going to carry over the same ratio.
- 01:12
We’ll take 24 times 2/3… to get 16…and that’s our answer. We're done!
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