# Trigonometry Lesson 1

### Measuring Angle Openness

Mary and Claire explore what it means for one angle to be more open than another. They also investigate how to measure that openness using both degrees and non-standard units.

##### Episode 1: Making Sense

Mary and Claire show images of angles they found in their everyday lives. Their images include both static angles and those that change over time, like the hand on a clock.

##### Episode 2: Making Sense

The students are asked to arrange eight angles in order from most open to least open. After they have determined an initial ordering, they check their work by tracing the angles onto patty paper and comparing them directly by overlaying one on top of the other.

##### Episode 3: Exploring

Mary and Claire estimate the measure of several angles in degrees. They do this by decomposing the angles into smaller angles that seem familiar (e.g., 90 degrees, 60 degrees, etc.)

##### Episode 4: Repeating Your Reasoning

Mary and Claire measure the openness of several angles using gips. Gips are a non-standard unit of measure. Eight gips fit into a full circle.

##### Episode 5: Repeating Your Reasoning

Mary and Claire construct an angle that measures 3.5 gips. They also calculate the measure of the angle they have created in degrees.

##### Episode 6: Reflecting

Mary and Claire describe openness. They also compare and contrast gips with degrees.