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Ch. 1 - Trigonometric Functions
Lial - Trigonometry 12th Edition
Lial12th EditionTrigonometryISBN: 9780136552161Not the one you use?Change textbook
Chapter 2, Problem 67

In each figure, there are two similar triangles. Find the unknown measurement. Give approximations to the nearest tenth.

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1
Identify the corresponding sides of the two similar triangles. Since the triangles are similar, their corresponding sides are proportional.
Set up a proportion using the lengths of the known sides from both triangles. For example, if side \(a\) in the smaller triangle corresponds to side \(A\) in the larger triangle, and side \(b\) corresponds to side \(B\), then write the proportion as \(\frac{a}{A} = \frac{b}{B}\).
Substitute the known side lengths into the proportion, leaving the unknown measurement as a variable (e.g., \(x\)).
Solve the proportion equation for the unknown variable by cross-multiplying and isolating the variable on one side of the equation.
Calculate the value of the unknown measurement and round your answer to the nearest tenth as requested.

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Key Concepts

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

Similarity of Triangles

Two triangles are similar if their corresponding angles are equal and their corresponding sides are proportional. This means one triangle is a scaled version of the other, which allows us to set up ratios between corresponding sides to find unknown lengths.
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30-60-90 Triangles

Proportionality of Corresponding Sides

In similar triangles, the ratios of the lengths of corresponding sides are equal. This property enables solving for unknown side lengths by setting up and solving proportion equations based on known side measurements.
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Finding Missing Side Lengths

Rounding and Approximation

When calculating unknown measurements, the results may be irrational or decimal numbers. Rounding to the nearest tenth means adjusting the value to one decimal place, which simplifies the answer while maintaining reasonable accuracy.
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