Angles in multiples of 5°, with a protractor printed on the page

The protractor is the most-lost tool in fourth grade. Half the class has one, a third have the wrong kind, and the lesson stalls while everybody shares. A sheet with the protractor already printed over each angle, so the child reads the number off the page, does not fix the lost-protractor problem. It does let the lesson happen.

What the sheet looks like

The lines, angles and polygons generator prints eight activities: name the angle (acute, right, obtuse, straight); measure the angle, with a half protractor printed over each one if you want it; draw the angle from a given ray; lines, rays and segments (parallel, perpendicular, intersecting, and line vs ray vs segment); classify triangles by sides with tick marks and by angles; polygons from triangle to decagon, regular or irregular, convex or concave; right angles in shapes to count and mark; or a mixed review. Pages hold 6, 8 or 12 problems.

Every angle is an exact multiple of 5°, so the answer key on the second page is exact, and a child reading 35° is right or wrong, not close.

Why it works

• Naming angles before measuring them gives a sanity check. If a child calls an angle obtuse and then measures 40°, one of those is wrong, and they can tell which.
• Drawing an angle from a ray is the reverse of measuring and exposes the child who reads the wrong scale on the protractor, because the drawn angle comes out as the supplement.
• The triangle page uses tick marks for equal sides, which is the notation they will meet for the next six years and is rarely taught on purpose.

Who it suits

Grades 3 to 5, ages eight to eleven. Name the angle and right angles in shapes are third-grade pages. Measure and draw, with the printed protractor at first and then without, are fourth grade, and classify triangles and the polygon page round out fifth. The mixed review is for the week before a test. For a child who still counts the sides of a shape, the shape attributes sheets are the step before this one.

Turn the printed protractor off once reading it is easy and hand over a real one. The angles are still multiples of 5, so a real protractor gives the same exact answers.