Geometry and Spatial Sense, Grades 4 to 6 - EduGains

• Show students an orange square pattern block, and then place it on the overhead projector.
Trace the square. Ask a student to identify one angle. Trace the angle, drawing an arc to
indicate the angle between the two line segments. Ask students what they know about this
kind of angle. Define a square corner as a right angle. Elicit from the class the fact that all
rectangles (including squares) have four right angles.
• Show students a green triangle pattern block, and then place it on the overhead projector.
Trace the triangle and ask a student to identify one angle. Trace the angle, drawing an arc
to indicate the angle between the two line segments. Repeat with the other two angles. Ask
students how these angles compare to those found in the square. Define an angle that is
smaller than a right angle as an acute angle.
• Show students a tan rhombus pattern block, and then place it on the overhead projec-
tor. Trace the rhombus. Ask a student to identify an angle larger than a right angle in the
rhombus. Trace the angle, drawing an arc to indicate the angle between the two line
segments. Define an angle that is larger than a right angle as an obtuse angle.
Create an anchor chart on the board or flip chart from the pattern block examples. Draw a
right angle, an acute angle, and an obtuse angle. Invite students to make observations and
name each angle.
WORKING ON IT
Ask the students, working as partners, to identify the number and types of angles found in the
remaining three pattern blocks (trapezoid, blue rhombus, and hexagon). Ask them to use the
angles they have found in the square, triangle, and tan rhombus as tools to help them.
Students are to communicate their findings in 2D4.BLM1: Pattern Block Angles Chart.
The chart includes:
• the pattern block
• the number and type of each angle found in the pattern block
• how they determined each angle
SAMPLE STUDENT STRATEGY
I used the square pattern block to help me find the angles in the trapezoid. The two top
angles were outside the square, so they are bigger than 90°, and are obtuse. The two bottom
angles are inside the square, so they are less than 90°, and are acute.
Next, give each student an index card or a small piece of tagboard. Have students use the
acute angle from the tan rhombus pattern block to draw a narrow angle on the tagboard or the
card and then cut it out. The resulting wedge can be used as a unit angle. Students will use this
unit angle to find and identify three other angles found anywhere in the classroom. They will
record their findings in the final three rows of the chart.
Students may use the pattern blocks to help them find relationships between the unit angle
and other angles. For example, students may discover that it takes three unit angles to make
a right angle.
Grade 4 Learning Activity: Two-Dimensional Shapes – Comparing Angles 81