Angles · Grade 4
In Grade 4 you learn: right angles; acute and obtuse angles; measuring angles with a protractor.
An angle measures an amount of turn. We measure angles in degrees with a protractor and sort them by size: acute, right, obtuse, straight and reflex.
Key facts
- Acute: less than 90°. Right angle: exactly 90°. Obtuse: between 90° and 180°.