Skip to main content
Ch. 2 - Acute Angles and Right Triangles
Lial - Trigonometry 12th Edition
Lial12th EditionTrigonometryISBN: 9780136552161Not the one you use?Change textbook
Chapter 3, Problem 3

CONCEPT PREVIEW Match each equation in Column I with the appropriate right triangle in Column II. In each case, the goal is to find the value of x.

x = 5 tan 38°

Verified step by step guidance
1
Step 1: Understand that each equation involving a trigonometric function (like tangent) relates an angle in a right triangle to the ratio of two sides. For example, \(x = 5 \tan 38^\circ\) means that \(x\) is the length of the side opposite the 38° angle, and 5 is the length of the adjacent side.
Step 2: Recall the definition of the tangent function in a right triangle: \(\tan \theta = \frac{\text{opposite side}}{\text{adjacent side}}\). This helps identify which sides correspond to the given values in the equation.
Step 3: For the equation \(x = 5 \tan 38^\circ\), recognize that the side with length 5 is adjacent to the 38° angle, and \(x\) is opposite that angle. So, look for the triangle in Column II where the side adjacent to 38° is 5 and the side opposite is labeled \(x\).
Step 4: Repeat this reasoning for each equation in Column I, matching the trigonometric function and given values to the sides and angles in the triangles in Column II.
Step 5: Confirm your matches by checking that the ratios from the equations correspond exactly to the side lengths and angles in the triangles, ensuring the correct pairing.

Verified video answer for a similar problem:

This video solution was recommended by our tutors as helpful for the problem above.
Was this helpful?

Key Concepts

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

Right Triangle Trigonometry

Right triangle trigonometry involves relationships between the angles and sides of a right triangle. The primary trigonometric ratios—sine, cosine, and tangent—relate an angle to the ratios of two sides, enabling the calculation of unknown side lengths or angles.
Recommended video:
04:39
45-45-90 Triangles

Tangent Function

The tangent of an angle in a right triangle is the ratio of the length of the side opposite the angle to the length of the adjacent side. It is often used to find a missing side when one side and an angle are known, as in the equation x = 5 tan 38°.
Recommended video:
5:43
Introduction to Tangent Graph

Solving for Unknown Sides Using Trigonometric Equations

To find an unknown side in a right triangle, set up an equation using the appropriate trigonometric ratio based on the given angle and known side. Solving this equation involves substituting known values and using inverse operations or calculator functions to isolate the variable.
Recommended video:
04:42
Solve Trig Equations Using Identity Substitutions
Related Practice
Textbook Question

CONCEPT PREVIEW Match each trigonometric function in Column I with its value in Column II. Choices may be used once, more than once, or not at all.

tan 45°

671
views
Textbook Question

CONCEPT PREVIEW Match each trigonometric function value or angle in Column I with its appropriate approximation in Column II.

Column I: 1.

tan 16°

Column II:

A. 88.09084757°

B. 63.25631605°

C. 1.909152433°

D. 17.45760312°

E. 0.2867453858

F. 1.962610506

G. 14.47751219°

H. 1.015426612

I. 1.051462224

J. 0.9925461516

572
views
Textbook Question

CONCEPT PREVIEW Match each trigonometric function in Column I with its value in Column II. Choices may be used once, more than once, or not at all.

csc 60°

646
views
Textbook Question

CONCEPT PREVIEW Match each trigonometric function value or angle in Column I with its appropriate approximation in Column II.

Column I: 1.

sin⁻¹ 0.30

Column II:

A. 88.09084757°

B. 63.25631605°

C. 1.909152433°

D. 17.45760312°

E. 0.2867453858

F. 1.962610506

G. 14.47751219°

H. 1.015426612

I. 1.051462224

J. 0.9925461516

562
views
Textbook Question

CONCEPT PREVIEW Match each trigonometric function value or angle in Column I with its appropriate approximation in Column II.

Column I: 1.

cot 27°

Column II:

A. 88.09084757°

B. 63.25631605°

C. 1.909152433°

D. 17.45760312°

E. 0.2867453858

F. 1.962610506

G. 14.47751219°

H. 1.015426612

I. 1.051462224

J. 0.9925461516

623
views
Textbook Question

Use a calculator to approximate the value of each expression. Give answers to six decimal places. sec 58.9041°

639
views