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Triangles Videos 32 videos
This video covers the different types of triangle. What makes a triangle isosceles, scalene, or equilateral? What about the different kinds of angl...
Sine is the opposite over the hypotenuse; cosine is the adjacent over the hypotenuse; and tangent is the opposite side over the adjacent side....
Someday you might be a big, fancy defense lawyer, and you'll have to prove that your client's triangle was congruent to the triangle in question. W...
ACT Math 4.2 Plane Geometry 251 Views
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Description:
ACT Math: Plane Geometry Drill 4, Problem 2. If x, y, and z are all integer values, which of the following cannot be the ratio of x:y:z?
Transcript
- 00:02
Time for your daily dose of shmoop. This won't hurt a bit.
- 00:06
If x, y, and z are all integer values, which of the following cannot be the ratio
- 00:10
of x:y:z?
- 00:12
And here are your options...
- 00:16
All we know about this triangle is that its angles are integer values, meaning that they
Full Transcript
- 00:20
aren't fractions or decimals. We also know that
- 00:23
the sum of a triangle's angles always equal 180 degrees. So... since the ratios of the
- 00:29
angles are always relative to 180 degrees, we have to look for the ratio that can't
- 00:35
allow the angles to be integers. In English, that basically means that, since
- 00:40
we're dividing up 180 degrees into little parts...
- 00:43
...180 has to be divisible by the total number
- 00:46
of parts in the ratio. The question is asking for the ratio that
- 00:50
can't be possible, so we have to look for the one that isn't divisible by 180. Let's
- 00:57
try: A: 1 + 2 + 3 = 6 and 180 / 6 = 30
- 01:04
B: 1 + 2 + 2 = 5, 180 / 5 = 36 C: 1 + 1 + 2 = 4, 180 / 4 = 45
- 01:16
D: 1 + 2 + 4 = 7, 180 / 7 = 25.715 E: 1 + 2 + 6 = 9, 180 / 9 = 20
- 01:30
Our answer is D because it doesn't produce an integer value, which means that each part
- 01:34
is not an integer, which ultimately means that the angles can't be integers either.
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