# Ch 35: WEST Math: Properties of Triangles

### About This Chapter

## WEST Math: Properties of Triangles - Chapter Summary

In preparation for the WEST Math teacher certification test, take advantage of the lessons in this chapter to sharpen your knowledge of the types of triangles, how to build them and their properties. Videos of the following topics are included in this chapter:

- Classifying the sides and angles of triangles
- Defining the exterior and interior angles of triangles
- Types of triangles
- Calculating the mean of a triangle
- Understanding the altitude, median and angle bisectors of a triangle
- Concurrent lines in a triangle

You'll have an easier time remembering the properties of triangles through detailed examples and practice problems. Instructors show you how to solve problems dealing with angles, concurrent lines and bisectors in a fun and informal way.

### Objectives of the WEST Math: Properties of Triangles Chapter

The subject areas in the Properties of Triangles chapter are included in the measurement and geometry section of the WEST Math test, which is 25% of the test. You'll be asked to solve problems using what you know about the properties of triangles and related shapes, such as circles, polygons and quadrilaterals. The entire exam is about 150 multiple-choice questions, which breaks down to about 38 questions on measurement and geometry. When it's time to take the test, you'll be given an on-screen scientific calculator to use and provided a formulas page for reference.

### 1. Triangles: Definition and Properties

What makes a shape a triangle? In this lesson, we'll explore the definition of a triangle, then analyze the parts of triangles, including the vertices, base and height.

### 2. Area of Triangles and Rectangles

How do you find out the area of rectangles and triangles? Learn how in this lesson! We'll look at the formulas, then practice solving problems for each shape.

### 3. 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.

### 4. Perimeter of Triangles and Rectangles

Without realizing it, we calculate and use the perimeter of triangles and rectangles in regular everyday situations. Learn more about the perimeter of triangles and rectangles in this lesson, and test your knowledge with a quiz.

### 5. Interior and Exterior Angles of Triangles: Definition & Examples

Knowing just a few things about the interior or exterior angles of triangles is sometimes all you need to put all the pieces together. Find out more in this lesson.

### 6. How to Identify Similar Triangles

Similar triangles have the same characteristics as similar figures but can be identified much more easily. Learn the shortcuts for identifying similar triangles here and test your ability with a quiz.

### 7. Median, Altitude, and Angle Bisectors of a Triangle

Line segments in triangles are just clutter; they have special names and qualities depending on how they're drawn. In this lesson, we'll learn about medians, altitudes and angle bisectors.

### 8. Properties of Concurrent Lines in a Triangle

Centroids, orthocenters, incenters, circumcenters, oh my! Don't worry though. In this lesson, we master the various terms for concurrent lines in triangles and match them to altitudes, angle bisectors, perpendicular bisectors and medians.

### 9. Properties of Right Triangles: Theorems & Proofs

In this lesson, you will learn about the properties of and theorems associated with right triangles, which have a wide range of applications in math and science. Specifically, we will discuss and prove the Pythagorean theorem and the right triangle altitude theorem. Let's get started.

### 10. The Pythagorean Theorem: Practice and Application

The Pythagorean theorem is one of the most famous geometric theorems. Written by the Greek mathematician Pythagoras, this theorem makes it possible to find a missing side length of a right triangle. Learn more about the famous theorem here and test your understanding with a quiz.

### 11. The Pythagorean Theorem: Converse and Special Cases

The Pythagorean Theorem is a famous theorem for right triangles. Watch this video to learn how the Pythagorean Theorem relates to the law of cosines and how the converse of the Pythagorean Theorem can help you identify right triangles.

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### Other Chapters

Other chapters within the NES Mathematics - WEST (304): Practice & Study Guide course

- WEST Math: Properties of Real Numbers
- WEST Math: Fractions
- WEST Math: Decimals & Percents
- WEST Math: Ratios & Proportions
- WEST Math: Units of Measure & Conversions
- WEST Math: Logic
- WEST Math: Reasoning
- WEST Math: Vector Operations
- WEST Math: Matrix Operations & Determinants
- WEST Math: Exponents & Exponential Expressions
- WEST Math: Algebraic Expressions
- WEST Math: Linear Equations
- WEST Math: Inequalities
- WEST Math: Absolute Value
- WEST Math: Quadratic Equations
- WEST Math: Polynomials
- WEST Math: Rational Expressions
- WEST Math: Radical Expressions
- WEST Math: Systems of Equations
- WEST Math: Complex Numbers
- WEST Math: Functions
- WEST Math: Piecewise Functions
- WEST Math: Exponential & Logarithmic Functions
- WEST Math: Continuity of a Function
- WEST Math: Limits
- WEST Math: Rate of Change
- WEST Math: Derivative Rules
- WEST Math: Graphing Derivatives
- WEST Math: Applications of Derivatives
- WEST Math: Area Under the Curve & Integrals
- WEST Math: Integration Techniques
- WEST Math: Applications of Integration
- WEST Math: Foundations of Geometry
- WEST Math: Geometric Figures
- WEST Math: Triangle Theorems & Proofs
- WEST Math: Parallel Lines & Polygons
- WEST Math: Quadrilaterals
- WEST Math: Circles & Arc of a Circle
- WEST Math: Conic Sections
- WEST Math: Geometric Solids
- WEST Math: Analytical Geometry
- WEST Math: Trigonometric Functions
- WEST Math: Trigonometric Graphs
- WEST Math: Solving Trigonometric Equations
- WEST Math: Trigonometric Identities
- WEST Math: Sequences & Series
- WEST Math: Set Theory
- WEST Math: Statistics Overview
- WEST Math: Summarizing Data
- WEST Math: Tables, Plots & Graphs
- WEST Math: Probability
- WEST Math: Discrete Probability Distributions
- WEST Math: Continuous Probability Distributions
- WEST Math: Sampling
- NES Mathematics WEST Flashcards