Skills Covered

How to Use This Pack

Five pages on angles and protractors. Page 1 treats an angle as a turn: a full turn is 360°, so a quarter turn is 360 ÷ 4 = 90° and a sixth of a turn is 60°. It names acute, right, obtuse, straight, and reflex angles, and counts the degrees a clock's minute hand turns. Page 2 reads angles drawn on a printed protractor: start from the 0 that the first ray passes through, on the inner or the outer scale, and check that an acute angle reads less than 90. Page 3 is measured with your own protractor: single angles, a slice of pizza, and the angles of a triangle and a four-sided shape. Every angle is drawn at its true size, so it measures the same on any printer. Page 4 draws angles of a given size from a ray. Page 5 finds unknown angles: when an angle is split into parts, the parts add up to the whole, so 35° + a = 90° and a = 55°.

In the Classroom

Before page 1, have students stand and turn a quarter turn, a half turn, and a full turn, and say the degrees. Before page 2, show on a large protractor that both scales name the same angles from opposite ends, and ask how to tell which number to read. On page 3, have partners check each other: line up the center mark on the vertex and the 0 line on one ray.

At Home

Find angles around the house: an open door, the hands of a clock, a slice of pizza. Ask your child whether each one is acute, right, or obtuse, and estimate its size before measuring it with a protractor.

Tips for Success

• A full turn is 360 degrees; a right angle is a quarter turn, 90 degrees
• Put the center mark on the vertex and the 0 line along one ray
• Read the scale that starts at 0 on that ray
• Estimate first: an acute angle is less than 90°, an obtuse angle more than 90°
• When an angle is split into parts, the parts add up to the whole angle