Extension work on lines, polygons, and triangles for grade 5 math can include the following:

1. Investigating different types of lines:
   • Have students explore and classify different types of lines, such as parallel, perpendicular, and intersecting lines.
   • Challenge them to find real-life examples of each type of line and explain their findings.
2. Exploring polygons:
   • Introduce students to different types of polygons, such as quadrilaterals, pentagons, hexagons, etc.
   • Ask them to identify and classify polygons based on their sides and angles.
   • Have students create their own polygons using various materials, such as straws or popsicle sticks.
3. Investigating triangles:
   • Teach students about different types of triangles, such as equilateral, isosceles, and scalene triangles.
   • Challenge them to find examples of each type of triangle in their environment.
   • Have students measure and compare the angles and sides of different triangles to discover any patterns or relationships.
4. Applying geometry concepts:
   • Provide students with real-life scenarios where they need to use their knowledge of lines, polygons, and triangles to solve problems.
   • For example, ask them to design a floor plan for a room using different polygons or calculate the perimeter and area of a triangle-shaped garden.
5. Geometry art:
   • Encourage students to create artwork using lines, polygons, and triangles.
   • They can use rulers and protractors to create geometric patterns or tessellations.
   • This activity allows them to apply their understanding of geometry while being creative.

Remember to adjust the difficulty level of these extension activities based on the students’ abilities and prior knowledge.