Section 5.4: Similar Triangles
Essential Ideas
  • Congruent figures have exactly the same size and shape. However, it is possible for figures to have exactly the same shape without having the same size. Such figures are called similar figures. In this section, we will focus on similar triangles.

  • Similar Triangle Property
    Two triangles are similar if two angles of one triangle are equal to two angles of the other triangle. If the triangles are similar, then their corresponding sides are proportional.

  • Pythagorean Theorem
    For any right triangle with sides a and b and hypotenuse c,
    a2 + b2 = c2

    Furthermore, if a2 + b2 = c2 for three sides of a triangle, then the triangle is a right triangle.

  • Trigonometric Ratios