00:01
All right, so in this problem, we want to figure out the coordinates of these little holes that are going to be drilled right here, the center of them.
00:10
So we're going to drill these little holes in this little metal kind of quarter circle plate.
00:16
So the radius of the quarter circle is 60 to begin with, but the holes don't go out that far.
00:24
It looks like the holes only go out 56 centimeters.
00:29
So you've got to think of the radius being 56 centimeters.
00:33
So all of these angles, it looks like it's 30 degrees.
00:36
Every 30 degrees they want to drill a little hole for 30 degrees.
00:43
So for this first hole to find the x coordinate.
00:47
So if you think of this little right triangle right here, here's the x coordinate in green.
00:57
Well, that side right there is the adjacent side.
01:00
We know that the radius, remember it's in a little bit, so it's 56 centimeters.
01:06
So if we want to find the x coordinate, the cosine of 30 is going to equal the x coordinate over the radius, which is 56.
01:20
Because we're not going all the way to the end of the circle according to this picture.
01:25
That's what i'm using.
01:26
So the cosine of 30 is square root of 3.
01:30
2, so that's off our unit circle.
01:35
So square root of 3 over 2 equals x over 56, multiply by 56.
01:42
So the x coordinate for the first point is going to be 28 square root of 3.
01:50
Okay, that's the x coordinate.
01:53
Now, if we want the y coordinate, so that's the red side, so we would take the sign of 30, equals x over 56.
02:06
The sign of 30 is just a half...