An angle is a geometric shape formed wherever two rays share a common endpoint. The place where the rays meet is called the vertex. Students create and manipulate angles in class using plastic straws and twist-ties.
Different types of angles are made by bringing the rays closer together or pushing them further apart. Students need to understand that angles are actually “wedges” of a 360-degree circle.
Acute angles are made by pushing the rays apart, more than 0 degrees but less than 90 degrees.
Right angles are exactly 90 degrees. They look like the corner of a square or rectangle.
Obtuse angles are more than 90 degrees but less than 180 degrees. They look wider than right angles and acute angles.
Straight angles are exactly 180 degrees. They look like a straight line.
Reflex angles are greater than 180 degrees but less than 360 degrees (less than a full circle). These angles have rays that are very far apart.