Find the value of each expression mentally.

Use a protractor to find the value of each angle measurement in degrees.

If you have time: Use a protractor to measure the labeled angles in the rhombus.

Tyler gives Lin a challenge: “Without using a protractor, draw four angles. All angles have their vertex at point P.”

Lin folds the paper twice, making sure each fold goes through point P. Then she traces the creases.

1. Your teacher will give you a sheet of paper. Draw a point on it. Then show how Lin might have met the challenge.
2. When Lin folds the paper, the creases form a pair of perpendicular lines. What do you think “perpendicular lines” mean?
3. Use Lin’s method to create a new pair of perpendicular lines through the same point. Trace the creases with a different color.

4. Which shapes have sides that are perpendicular to one another?

   Mark the perpendicular sides. Explain how you know the sides are perpendicular.