Classifying objects is necessary for defining concepts. Introduce classification activities where students must group shapes based on their characteristics. Cut out several examples of quadrilaterals and parallelograms, mix them up and have students separate them into two distinct groups. This can also be done for shapes that are convex or concave. Have students write rules for how they grouped the shapes and display them around the room as a reference throughout your geometry unit.
Explore basic geometric shapes for symmetry. Using squares, rectangles, triangles and circles, have students draw lines of symmetry. Lines of symmetry divide an object into two parts that look exactly the same, and when folded over on top of each other would match up perfectly. Once students are comfortable using basic geometric shapes, move onto more complex shapes such as faces and tessellations. Challenge students to create shapes that have a specified number of lines of symmetry.
Drawing and measuring angles is an essential skill in geometry. Give students polygons and have them measure the interior angles using a protractor. Ask students to draw angles with their compasses that measure a specified degree. Create a class challenge by having students draw angles of unknown degrees and have their classmates try to find the angle measure using their protractors.
Introduce the equations for finding the areas of rectangles, circles and triangles. Give students several examples of each of these shapes and have them find their areas using the proper equation. When students are comfortable finding area, introduce the concepts of perimeter and diameter. Have students find the perimeter or diameter of several rectangles, triangles and circles.