# Ch 12: Trigonometric Properties of Triangles

### About This Chapter

## Trigonometric Properties of Triangles - Chapter Summary

Get all the information you need about the trigonometric properties of triangles without setting foot in a classroom. Lessons in this chapter can be viewed whenever your schedule permits using any computer, smartphone or tablet. Take an in-depth look at incircles, excircles, half angles and other aspects of triangles with help from expert instructors. Once you've completed this chapter, you will be ready to:

- Use angles and sides to classify triangles
- Describe the rules for half-angle formulas
- Find the area of a triangle using sine
- Define and explain the application and construction of incircles and excircles

Feel free to navigate the lessons in any order you desire. Revisit them several times to make sure you absorb the information you review. Take multiple-choice quizzes and a chapter exam to assess your comprehension of the trigonometric properties of triangles. If you hit a snag and need to clarify any details, be sure to submit your questions using the Ask Our Experts feature in the Dashboard.

### 1. Classifying Triangles by Angles and Sides

Not all triangles are the same. There are equilateral, isosceles and scalene triangles. Then there are right, acute and obtuse triangles. In this lesson, we'll learn how to classify triangles using their sides and angles.

### 2. Half Angle: Rule, Formula & Examples

If we know at least the cosine of an angle, we can use formulas to find the sine, cosine and tangent of half that angle. These formulas are called half-angle formulas. In this lesson we state half-angle formulas, describe the rules for using them, and present examples.

### 3. Using Sine to Find the Area of a Triangle

Since you first started working with triangles in math class, chances are you've been exposed to the formula for the area of a triangle. However, that is only good if you know the height of the triangle. This lesson shows you how to get around that.

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### Other Chapters

Other chapters within the AP EAMCET E (Engineering): Study Guide & Test Prep course

- Principles of Mathematical Functions
- Mathematical Induction
- Overview of Matrices
- Overview of Complex Numbers
- Understanding Quadratic Expressions
- Theory of Equations
- Permutations & Combinations in Algebra
- Understanding the Binomial Theorem
- Understanding Partial Fractions
- Fundamental Elements of Trigonometry
- Understanding Hyperbolic Functions
- Vector Algebra
- Measures of Dispersion
- Principles of Probability
- Coordinate Geometry Overview
- Lines & Circles
- Conic Sections Overview
- Three-Dimensional Coordinates
- Limits & Continuity
- Differentiation in Calculus
- Integration in Calculus
- Understanding Differential Equations
- Understanding the Basics of Physics
- Units & Measurement in Physics
- Understanding Motion in Physics
- Systems of Particles & Rotational Motion
- Work, Energy & Power Overview
- Overview of Oscillations
- Overview of Gravitation
- Properties of Solids, Fluids & Gases
- Thermal Properties of Matter
- Rays, Waves & Wave Optics
- Understanding Electricity
- Magnetic Force & Electromagnetism
- Currents, Waves & Circuits
- Communication Systems
- Atoms & Nuclei
- Atomic Structure Overview
- Understanding Elements & the Periodic Table
- Chemical Bonding & Molecular Structure
- States of Matter in Chemistry
- Basic Stoichiometry
- Thermodynamics & Chemistry
- Chemical Equilibrium & Acid-Bases
- Hydrogen & Hydrogen Compounds
- Alkali & Alkaline Earth Metals
- Environmental Chemistry
- Understanding Organic Chemistry
- Solids in Chemistry
- Electrochemistry & Chemical Kinetics
- Surface Chemistry
- Metallurgy Overview
- Polymers Overview
- Understanding Biomolecules
- Everyday Chemistry
- AP EAMCET E (Engineering) Flashcards