### Home > GC > Chapter 5 > Lesson 5.1.4 > Problem 5-40

5-40.

in the triangle at right. She lost her scientific calculator, but luckily her teacher told her that

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

. Label added, third angle, theta = 23 degrees.

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. Label added, short side is y.Which equation can be used to solve for

?Without a calculator, how could Estelle find

? Explain.