Understanding why angles on a straight line add up to 180 degrees is an important idea in Year 7 Mathematics! Let’s make this easy to understand.

What is a Straight Line?

A straight line is the shortest way to connect two points. Think of it like a long, flat road. When we talk about angles on a straight line, we’re looking at the different parts of that line.

Why Do They Add Up to 180 Degrees?

To understand why angles on a straight line always add up to 180 degrees, imagine a straight line. It’s like the pages of an open book. Now, picture another line crossing it.

1. When two angles share a straight line, they fit together perfectly to make the full angle of that line.
2. The full angle of a straight line is called a straight angle, and it measures 180 degrees.

Examples to Help You Understand

• If one angle is 70 degrees, the other angle on the line must be 180 degrees - 70 degrees = 110 degrees. Together, they make a straight angle.

• If you have angles of 40 degrees and 140 degrees, they also add up to 180 degrees: 40 degrees + 140 degrees = 180 degrees.

Conclusion

So, every time you see angles on a straight line, remember—they work together to create a full angle of 180 degrees. This makes geometry like a fun puzzle to solve!