Learning to find Proportion
How to check for proportion in a design.
In this case, triangles are used to map the size, spacing and layout of the figures created by the artist. Use the construction tools to show how the relationships are proportional.
Check to see if there are triangles which are similar using the SSS Similarity Theorem.
1. Use the polygon tool to outline the top smallest triangle.
2. Use the polygon tool to outline the largest triangle.
3. Use the distance tool to measure all three sides of the smaller triangle.
4. Use the distance tool to measure all three sides of the larger triangle.
5. Compare the ratios of the small triangle sides to the corresponding big triangle sides. Use the calculator to see if the scale factors are the same (or nearly the same). Triangles whose corresponding side lengths are proportional are similar by the SSS Similarity Theorem.
Check to see if there are triangles which are similar using the AA Similarity Theorem.
6. Uses the polygon tool to trace the triangle in the center that surrounds the largest cherub.
7. Use the angle tool to measure the three angles in the triangle.
8. Use the angle tool to measure any to angles of the largest triangle. If those two angles match any two angles in the triangle in the center, then by the AA Similarity Theorem they are similar.
Check to see if any other triangles are proportional using the SSS, ASA, or AA Theorems.
Proportion describes the relationship between the dimensions of different elements and an overall composition.
Can you see any proportional relationships in the image below? Describe any that you see.