Right Triangle Trigonometry

Right Triangle Trigonometry

1. How to find a missing SIDE length of a right triangle.

   • If you know two side lengths...
     • Use the Pythagorean Theorem. a²+b²=c²
   • If you know one side length and one acute angle measure...
     • Use a trig ratio (sine, cosine, tangent) SOHCAOTOA

2. How to find a missing ANGLE measure of a right triangle.

   • If you know one acute angle measure...
     • Use the Triangle Sum Theorem m∡A + m∡B + m∡C = 180°
   • If you know two side lengths...
     • Use inverse trig (arcsin, arccos, arctan)
       • arcsin is the same as sin^-1 in your calculator

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