Angles can be difficult when students judge the length of the arms instead of the amount of turn. A movable model makes the turn visible and gives the class a shared benchmark.
The Daily Maths Review angles tool lets teachers drag an angle arm, use a slider, jump to common preset angles and show the angle name, degree measure and comparison with a right angle.
Start from a right angle
Begin at 90 degrees and ask students to describe what makes it a right angle. Then move the arm slightly smaller and larger so students can compare each turn with the benchmark.
- Use 30 and 60 degrees for acute angle examples.
- Use 120 degrees when students are learning obtuse angles.
- Use 180 degrees to show a straight angle.
- Use 270 degrees when introducing reflex angles.
Ask students to predict the name
Before revealing the label, ask students whether the angle is less than, equal to or greater than a right angle. This keeps the explanation tied to the amount of turn.
Show 90 degrees, drag to a smaller angle, drag to a larger angle, then use random angle and ask students to justify the label before checking it.
Move from modelling to practice
After students have used the right-angle benchmark aloud, move into the angles practice app. If students confuse acute and obtuse, return to the tool and compare each angle with 90 degrees again.