Video Transcript - Problems with Parallel Lines

Welcome to another video from UltimateAlgebra.com. In this video we will be solving some problems using the properties of parallel lines we learned in the previous video.

This video is purely for problem solving, so we are not going to mention the names of the properties we are using. You can always refer to the previous video if you care about the name of the property we are using.

There are quite a few ways of looking at this but I prefer to label the angles like two circles. So here I have labelled it A, B, C, D. Then I labelled this E, F, G and H.

Now we have A, B, C to H.

Noticed that I have alternated the colors. So A is red, B is blue, C is red and D is blue. I have done the same for E, F, G and H.

Now we can say that

1. all the angles with color code Red are the same. So A = C = E = G
2. all the angles with color code Blue are also the same. So B = D = F = H
3. any angle coded red plus any angle coded blue is equal to 180 degrees.

Example A + F = 180

C + H = 180.

This is all you need to solve questions here.

Everything here is for learning purpose, when you get used to it you won’t even need this.

Let’s take a real question

Given the figure below find angles x and y.

Our first work will be to quickly color code the sections. I’m just putting blue and red dots.

We see that the angle 40 degrees is blue coded. Therefore, all blue coded angles will be 40 degrees.

Angle X is blue coded so it will also be 40 degrees.

Next we know that the angle Y is coded Red and the 40 degrees is blue coded. We can say that angle Y plus 40 = 180 degrees. We solve for Y. to get angle Y equal to 140 degrees.

So let’s say we introduce angle M and we want to find it. We just look at the color code. It is red. So the angle M is 140 degree.

Hope you get what’s going on. We will end this video here. Have a great day. Good bye.