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Ch. 2 - Graphs of the Trigonometric Functions; Inverse Trigonometric Functions
Blitzer - Trigonometry 3rd Edition
Blitzer3rd EditionTrigonometryISBN: 9780137316601Not the one you use?Change textbook
All textbooksBlitzer 3rd EditionCh. 2 - Graphs of the Trigonometric Functions; Inverse Trigonometric FunctionsProblem 7
Chapter 2, Problem 7

Solve the right triangle shown in the figure. Round lengths to two decimal places and express angles to the nearest tenth of a degree. a = 30.4, c = 50.2

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Identify the sides and angles in the right triangle. Here, side \(a\) corresponds to \(p\), side \(c\) corresponds to \(r\) (the hypotenuse), and side \(b\) corresponds to \(q\). Given: \(a = 30.4\) and \(c = 50.2\).
Use the Pythagorean theorem to find the missing side \(b\) (or \(q\)):
\[b = \sqrt{c^2 - a^2} = \sqrt{50.2^2 - 30.4^2}\]
Calculate angle \(Q\) using the sine function, since \(\sin(Q) = \frac{\text{opposite}}{\text{hypotenuse}} = \frac{a}{c}\):
\[Q = \sin^{-1}\left(\frac{a}{c}\right) = \sin^{-1}\left(\frac{30.4}{50.2}\right)\]
Calculate angle \(P\) by subtracting angle \(Q\) from 90 degrees (since the triangle is right-angled):
\[P = 90^\circ - Q\]

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Right Triangle Properties

A right triangle has one angle of 90 degrees, and the side opposite this angle is the hypotenuse, the longest side. The other two sides are called legs. Understanding these properties helps in applying trigonometric ratios and the Pythagorean theorem to solve for unknown sides or angles.
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30-60-90 Triangles

Pythagorean Theorem

This theorem states that in a right triangle, the square of the hypotenuse (longest side) equals the sum of the squares of the other two sides. It is expressed as r² = p² + q². This relationship is essential for finding missing side lengths when two sides are known.
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Solving Right Triangles with the Pythagorean Theorem

Trigonometric Ratios (Sine, Cosine, Tangent)

Trigonometric ratios relate the angles of a right triangle to the ratios of its sides. Sine = opposite/hypotenuse, Cosine = adjacent/hypotenuse, and Tangent = opposite/adjacent. These ratios are used to find unknown angles or sides when some measurements are given.
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Sine, Cosine, & Tangent of 30°, 45°, & 60°
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