Capítulo 13 · Neste capítulo você vai
Similarity of triangles and power of point
- define similar triangles and the similarity ratio;
- use the fundamental theorem and the similarity cases;
- calculate unknown measurements by proportion;
- apply the power of a point in relation to a circle.
Two similar triangles have the same shape, but not necessarily the same size. The idea appears on maps and plans (scales), in shadows, in photography and even in the laws of optics: Pierre de Fermat (17th century) explained the reflection and refraction of light with arguments in which similar triangles appear at each step. And, as we saw in chapter 12, Thales used similarity to measure the height of a pyramid by its shadow.
