This activity is about calculating the unknown angle on a straight line.

The angles at a point on a straight line add up to 180°.

180° is half a complete revolution.

Notice that **35° + 145° = 180°**

**e.g. Find the missing angle in degrees.**

The missing angle is 180° - 65° = **115°**

Want to understand this further and learn how this links to other topics in maths?

Why not watch this video?