WEBVTT
00:00:01.150 --> 00:00:04.060
How many lines of symmetry does the figure have?
00:00:06.310 --> 00:00:13.370
Lines of symmetry are the places where one-half of the image is a reflection of the other half.
00:00:15.160 --> 00:00:23.080
We want to know at how many places in this figure is one-half the reflection of the other half.
00:00:24.530 --> 00:00:33.510
If we fold our figure right down the middle, the right side will completely cover the left side.
00:00:35.210 --> 00:00:39.290
What would happen if we try to fold it in half horizontally?
00:00:41.110 --> 00:00:46.660
It would look like this, because the bottom is not a reflection of the top.
00:00:48.720 --> 00:01:00.080
If we try to fold it at another vertical line, if we try to fold it here, we do not find one-half being the reflection of the other half.
00:01:01.220 --> 00:01:11.270
For this irregular image, there’s only one way to fold it so that the halves line up perfectly, at the original blue line we drew.
00:01:13.600 --> 00:01:17.630
And so this figure has one line of symmetry.