A clock with movable hands can be used to model specific angles. After introducing the classifications of acute, right, obtuse and straight angles, students can be instructed to use a clock to find examples of each type of angle. For example, the time 12:05 models an acute angle, 12:15 models a right angle, 12:20 models an obtuse angle and 12:30 models a straight angle. Students can be challenged to find all of the possible times that model a straight angle.
A fun way to build and classify angles is to use straight food. Examples include Twizzlers, dried spaghetti and pretzel sticks. Students can be instructed to build angles modeling various types of angles. Specific angle measurements can be given with instructions to construct an angle of that measurement using estimation skills. Protractors can be used to determine how close the estimated angle is to the actual measurement.
A set of pattern blocks consists of a triangle, trapezoid, two types of a rhombus and hexagon. Students can be instructed to identify the angles in each block. Blocks can be arranged to compare angle sizes. Two or more blocks can be combined to form a right, obtuse or straight angle. Protractors can be used to find the actual measurement of each angle. The sums of the interior angles of the polygons can be determined by measuring them.
Incorporating art with mathematics helps struggling students use visual skills to reinforce geometric properties while encouraging their creative abilities. Partial drawings can be distributed to students with instructions to construct specific angle types to finish the drawing. For example, students can be given a partial drawing of a bird without a beak. They can be instructed to finish the drawing by constructing an acute angle to form the beak. The bottom of a house can be added by using right angles. The roof of a house can be constructed by adding two obtuse angles.