http://www.ck12.org Chapter 8. Right Triangle Trigonometry
m^6 A: Use Triangle Sum Theorem
62 ◦+ 90 ◦+m^6 A= 180 ◦
m^6 A= 28 ◦Example 5:Solve the right triangle.
Solution:Even though, there are no angle measures given, we know that the two acute angles are congruent, making
them both 45◦. Therefore, this is a 45-45-90 triangle. You can use the trigonometric ratios or the special right triangle
ratios.
TrigonometricRatios
tan 45◦=15
BC
sin 45◦=15
AC
BC=
15
tan 45◦= 15 AC=
15
sin 45◦≈ 21. 21
45-45-90TriangleRatios
BC=AB= 15 ,AC= 15
√
2 ≈ 21. 21
Real-Life Situations
Much like the trigonometric ratios, the inverse trig ratios can be used in several real-life situations. Here are a couple
examples.
Example 6:A 25 foot tall flagpole casts a 42 feet shadow. What is the angle that the sun hits the flagpole?