Area, perimeter and dissection
Build a model, justify why it applies and check the result.
IKMC Grades 9-10 - Selected Topics
Distinguish perimeter (length of the boundary) from area (surface covered), and explain why internal edges are not part of the perimeter.
Compare the areas of triangles that share a common height.
Cut and rearrange a shape without overlaps or gaps, and explain why its area is unchanged.
Explain why multiplying all lengths by k multiplies the area by k².