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Home > CCG > Chapter 5 > Lesson 5.1.4 > Problem 5-46


Estelle is trying to find in the triangle at right. She lost her scientific calculator, but luckily her teacher told her that , , and .  

A right triangle with a base of 18 and a hypotenuse of x. An angle opposite the 18 side is 67 degrees.

  1. Write an equation that Estelle could use to solve for .

Use the Triangle Angle Sum Theorem to calculate the missing angle, this means all the angles in a triangle total .

Place a "" on the missing side. Write the trigonometric ratios for the angle, reference the Math Note box in Lesson 5.1.2 for extra help.

The third angle is 23 degrees.

The short side of the triangle is y.

Which equation can be used to solve for ?

  1. Without a calculator, how could Estelle find ? Explain.