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9.07 Angles on a straight line

Lesson

Are you ready?

Do you remember how many degrees are in a full turn? Let's try this problem to review. 

How many $1^\circ$1° angles fit into a full circle?

Learn

A straight line is half of a full turn, so it has a measure of $180$180 degrees.
This also means that angles on a straight line will add up to $180$180 degrees.

Let's learn more about angles on a straight line.

Apply

Find the size of the missing angle.

  1. $=$= $\editable{}$$^\circ$°

Remember!

Angles on a straight line always add up to $180$180 degrees.

Outcomes

MA.4.GR.1.2

Estimate angle measures. Using a protractor, measure angles in whole-number degrees and draw angles of specified measure in whole-number degrees. Demonstrate that angle measure is additive.

MA.4.GR.1.3

Solve real-world and mathematical problems involving unknown whole-number angle measures. Write an equation to represent the unknown.

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