Geometry

Identify and draw perpendicular/parallel lines and obtuse/acute/right angles

• With your child, look around your home for acute, right, and obtuse angles and for perpendicular and parallel lines. You’ll likely discover that right angles, perpendicular lines, and parallel lines are the easiest to find! You might find acute and obtuse angles, among other places, on clocks, on the molding around windows and doors, on windows that crank open, and on hinged picture frames.

Classify 2D figures based on the presence/absence of parallel or perpendicular lines or the presence/absence of specific angles

• Go for a walk around your neighborhood or to a local park or playground, and ask your child to take pictures of different shapes. Try to find shapes that are composed from other shapes. Print out the pictures, or use software to design a slide show of the photos. Have your child add captions to describe the shapes by using the vocabulary she has been learning in school.

Determine the approximate measures of angles in degrees using a protractor

Determine the measure of an angle formed by two adjacent angles given one or both angles

• Practice, with your child, making quarter-turns with your bodies. Stand and face the same wall. Next, close your eyes. Take turns giving a directive to spin 90°, 180°, 270°, or 360° to the right or left. After each spin, open your eyes to see whether you are both facing the same wall. If you are not, discuss who is facing the correct direction.
• Draw a right angle. Ask your child to split the right angle into two smaller angles by drawing a ray that extends from the right angle. Prompt your child to measure one of the angles by using a protractor, and then ask him to mathematically determine the measure of the other angle (i.e., subtract the measured angle from 90° or add up to 90°). As a final step, he can use the protractor to prove that his calculation of the angle measure is correct. (Extend the activity by drawing and using a straight angle instead.)