Geometry

Similar Triangles

When triangles have equal angles

  • Primary school
  • about 3 min
  • 7 of 9 in the family
Not started
a₁a₂=k·a₁b₁b₂=k·b₁Equal angles → similar triangles
Scale k = 1.80
a1a2=b1b2=c1c2=k=11.80\frac{a_1}{a_2} = \frac{b_1}{b_2} = \frac{c_1}{c_2} = k = \frac{1}{1.80}

Similar triangles have equal angles and proportional sides. Foundation of trigonometry: sine depends only on the angle, not the size of the triangle.