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Ch. 1 - Trigonometric Functions
Lial - Trigonometry 12th Edition
Lial12th EditionTrigonometryISBN: 9780136552161Not the one you use?Change textbook
Chapter 2, Problem 54

Convert each angle measure to decimal degrees. If applicable, round to the nearest thousandth of a degree. See Example 4(a). 82° 30'

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1
Understand that the angle is given in degrees and minutes: 82° 30'. Recall that 1 degree (°) equals 60 minutes (').
To convert the minutes to decimal degrees, use the formula: \(\text{Decimal Degrees} = \text{Degrees} + \frac{\text{Minutes}}{60}\).
Substitute the given values into the formula: \(82 + \frac{30}{60}\).
Simplify the fraction \(\frac{30}{60}\) to get 0.5, so the expression becomes \$82 + 0.5$.
Add the values to find the decimal degree measure, then round to the nearest thousandth if necessary.

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Key Concepts

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

Degrees, Minutes, and Seconds (DMS) Notation

Angles can be expressed in degrees (°), minutes ('), and seconds ("), where 1 degree equals 60 minutes and 1 minute equals 60 seconds. This notation is commonly used in navigation and surveying to represent precise angle measures.
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i & j Notation

Conversion from Minutes to Decimal Degrees

To convert minutes to decimal degrees, divide the number of minutes by 60 since there are 60 minutes in one degree. For example, 30 minutes equals 0.5 degrees, which is added to the whole degrees to get the decimal degree value.
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Rounding Decimal Degrees

After converting to decimal degrees, rounding is often necessary for simplicity and clarity. Rounding to the nearest thousandth means keeping three digits after the decimal point, which balances precision and readability in angle measurements.
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