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Ch. 4 - Laws of Sines and Cosines; Vectors
Blitzer - Trigonometry 3rd Edition
Blitzer3rd EditionTrigonometryISBN: 9780137316601Not the one you use?Change textbook
Chapter 4, Problem 27

In Exercises 25–30, use Heron's formula to find the area of each triangle. Round to the nearest square unit.
a = 14 meters, b = 12 meters, c = 4 meters

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1
Identify the side lengths of the triangle: \(a = 14\) meters, \(b = 12\) meters, and \(c = 4\) meters.
Calculate the semi-perimeter \(s\) of the triangle using the formula: \(s = \frac{a + b + c}{2}\).
Substitute the values of \(a\), \(b\), and \(c\) into the semi-perimeter formula to find \(s\).
Apply Heron's formula to find the area \(A\) of the triangle: \(A = \sqrt{s(s - a)(s - b)(s - c)}\).
Substitute the values of \(s\), \(a\), \(b\), and \(c\) into Heron's formula and simplify under the square root to find the area before rounding.

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Key Concepts

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

Heron's Formula

Heron's formula calculates the area of a triangle when the lengths of all three sides are known. It uses the semi-perimeter, s = (a + b + c) / 2, and the area is found by √[s(s - a)(s - b)(s - c)]. This method avoids needing the height or angles.
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Quadratic Formula

Semi-perimeter of a Triangle

The semi-perimeter is half the perimeter of a triangle, calculated as s = (a + b + c) / 2. It is a key intermediate value in Heron's formula, simplifying the area calculation by incorporating all three side lengths into one term.
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30-60-90 Triangles

Rounding and Units in Measurement

After calculating the area, it is important to round the result to the nearest whole number as specified. Additionally, the units of area are the square of the length units (e.g., square meters), reflecting the two-dimensional nature of area.
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Introduction to the Unit Circle