McGraw Hill Glencoe Algebra 2, 2012
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McGraw Hill Glencoe Algebra 2, 2012 View details
1. Trigonometric Functions in Right Triangles
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Exercise 52 Page 797

Use the sine ratio to find m∠ A.

m∠ A = 28.1^(∘)
m∠ B = 61.9 ^(∘)
b = 15

Practice makes perfect

Let's analyze the right triangle that satisfies the given conditions.

We will find the missing measures one at a time. In this case, this means that we want to find m ∠ A, m ∠ B, and b.

Angle Measures

We can find m ∠ A using the sine ratio.

The sine of ∠ A is the ratio of the length of the leg opposite ∠ A to the length of the hypotenuse. Sine=Opposite/Hypotenuse ⇒ sin A =8/17 By the definition of the inverse sine, the inverse sine of 817 is the measure of ∠ A. To find it, we will use a calculator.

m∠ A=sin ^(-1) 8/17
m∠ A = 28.072486...^(∘)
m ∠ A ≈ 28.1^(∘)

To find m∠ B, recall that the acute angles of a right triangle are complementary. Therefore, m ∠ A and m ∠ B add to 90^(∘). m ∠ A + m ∠ B = 90^(∘) Now, we can substitute the rounded measure of ∠ A in our equation and find the measure of ∠ B. 28.1^(∘) + m∠ B = 90^(∘) ⇔ m ∠ B =61.9^(∘)

Side Length

Finally, we can find the measure of b. To do it, we can use the Pythagorean Theorem. a^2 + b^2 = c^2 Let's substitute the known lengths, a = 8 and c= 17, into this equation to find b.

a^2 + b^2 = c^2
8^2 + b^2 = 17^2
â–¼
Solve for b
64 + b^2 = 289
b^2= 225
b = 15