00:01
What's the definition of a regular octagon? that's an octagon with eight equal sides, and their interior angles are all equal as well.
00:07
Okay, so the radius going to this regular octagon is six inches.
00:14
And recall, this goes to every single point that intersects.
00:19
I'm trying to find out what my side length of one of the octagon is.
00:26
So what's my angle here? well, what's the angle around the entire circle? 306 degrees.
00:32
How many different slices in how many different triangles am i cutting this into eight different triangles, right? because it's an octagon, so 360 divided by 8, about 45 degrees.
00:43
Okay, so this angle is 45 degrees.
00:48
What are each of these angles down here? well, does it really matter? what i need to do is i need to find this angle.
01:00
How can i find that angle over that side? well, one way i can do this is i can create a right triangle.
01:05
This cuts the side and half.
01:06
This is six.
01:08
This angle right here, 45 divided by 2, is going to be 22 .5 degrees, and i'll enlarge this, so it's a little easier to see.
01:17
6, 22 .5 degrees, and i just care about the side length here.
01:23
In a right triangle, how can i find the missing side? well, what relates angles in side? sign, cosine, and tangent...