Scale Diagrams and Similar Figures
Similar figures have the same shape but different sizes — all corresponding angles are equal and all corresponding sides are proportional. Shadow problems, map scales, and architectural drawings all rely on this relationship. Students use proportions to find unknown lengths, building proportional reasoning skills that connect back to earlier ratio work and forward to trigonometry.
What students explore
Similar figures have the same shape but different sizes — all corresponding angles are equal and all corresponding sides are proportional. Shadow problems, map scales, and architectural drawings all rely on this relationship. Students use proportions to find unknown lengths, building proportional reasoning skills that connect back to earlier ratio work and forward to trigonometry.
Key ideas
Identify similar polygons and state their properties. Calculate missing side lengths in similar figures using proportions. Draw and interpret scale diagrams. Apply similarity to real-world problems: maps, shadows, photography.
Putting it together
Apply these ideas through worked examples, guided practice, and real-world problems.