Students open and close an angle to see how it’s measured in degrees, and learn to name the three main kinds: acute, right, and obtuse.
Students will be able to…
A door barely open, a square corner, a door flung wide — all angles. How do we measure how “open” an angle is, and what do we call each kind?
Project this and open the angle from 0° to 180°. Have students watch the degree measure change and name each kind of angle.
Tap any phase to open the teacher moves and student actions.
A door barely open vs. wide open — which angle is bigger?
Teacher teaches degrees.
Class drives the Angle Maker.
Students measure and classify.
Name that angle.
Aligned to the Common Core State Standards for Mathematics, including the Standards for Mathematical Practice.
Draw points, lines, rays, angles (right, acute, obtuse), and identify them in figures.
Recognize angles as geometric shapes formed by two rays, measured in degrees.
Measure angles in whole-number degrees using a protractor.
Attend to precision when measuring and classifying angles.
Preview the three formative checks. Tap “Sample answer” to see what mastery looks like — hide them before you print for students.
Have students find and photograph or sketch acute, right, and obtuse angles around the school, then measure a few with a protractor. A printable angle-hunt sheet is in the Math library.
Tap a card to flip it, then rate whether you knew it. Built from this lesson’s vocabulary.
A quick self-check with instant feedback, drawn from this lesson’s key terms.
A print-and-go review sheet with a built-in answer key. Tap “Show answer key” to reveal answers, or print the clean version for students.