# Ch 42: WEST Middle Grades Math: Triangles

### About This Chapter

## WEST Middle Grades Math: Triangles - Chapter Summary

This chapter uses enticing video lessons to make your study of triangles effective and fun. Lessons cover the concepts you'll likely run into on the WEST Middle Grades Math assessment, such as:

- Triangle properties and classifications
- Interior and exterior angles
- Identifying similar triangles
- How to construct the median of a triangle
- Altitude, mean and angle bisectors
- Triangle and geometric construction

Test your understanding of the concepts by taking the short, multiple-choice self-assessment after each lesson. Reach out to our instructors if you need any help with the material.

### Objectives of the WEST Middle Grades Math: Triangles Chapter

Measurement and geometry questions make up 25% of the WEST Middle Grades Math certification exam. Use this chapter to review the triangle ideas likely to appear on the test and to introduce yourself to the exam format - our lesson quizzes mimic the WEST style so you can get comfortable with it.

The computer-administered assessment includes three other content areas: statistics, probability and discrete math (25%); number sense and operations (17%); and algebra and functions (33%). There are 150 tasks in total, and you'll be given four and a quarter hours to finish them all.

### 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. 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.

### 3. 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.

### 4. 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.

### 5. Angles and Triangles: Practice Problems

Want more practice solving with angle pairs? How about more review for solving angles in triangles? Look no further. Get more practice here, and test your ability with a quiz.

### 6. Constructing the Median of a Triangle

If you have one triangle and want to divide it, you can use a median line. Medians have special geometric properties that we'll learn about in this lesson.

### 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. Constructing Triangles: Types of Geometric Construction

When you're asked to construct a triangle, it's time to break out that compass and straight edge! In this lesson, find out how to construct triangles no matter what you're given.

### 9. 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.

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### Other Chapters

Other chapters within the WEST Middle Grades Mathematics (203): Practice & Study Guide course

- WEST Middle Grades Math: Basic Arithmetic Operations
- WEST Middle Grades Math: Solving Math Word Problems
- WEST Middle Grades Math: Properties of Numbers
- WEST Middle Grades Math: Estimating & Rounding
- WEST Middle Grades Math: Number Theory
- WEST Middle Grades Math: Roots & Radical Expressions
- WEST Middle Grades Math: Exponents & Exponential Expressions
- WEST Middle Grades Math: Scientific Notation
- WEST Middle Grades Math: Simplifying Whole Number Expressions
- WEST Middle Grades Math: Integers
- WEST Middle Grades Math: Rational Numbers
- WEST Middle Grades Math: Introduction to Fractions
- WEST Middle Grades Math: Operations with Fractions
- WEST Middle Grades Math: Introduction to Decimals
- WEST Middle Grades Math: Operations with Decimals
- WEST Middle Grades Math: Percents
- WEST Middle Grades Math: Money & Consumer Math
- WEST Middle Grades Math: Number Patterns & Sequences
- WEST Middle Grades Math: Properties of Functions
- WEST Middle Grades Math: Graphing Functions
- WEST Middle Grades Math: Negative Numbers
- WEST Middle Grades Math: Absolute Value
- WEST Middle Grades Math: Inequalities
- WEST Middle Grades Math: Factoring
- WEST Middle Grades Math: Monomials & Polynomials
- WEST Middle Grades Math: Writing Algebraic Expressions
- WEST Middle Grades Math: Basic Algebraic Expressions
- WEST Middle Grades Math: Algebraic Distribution
- WEST Middle Grades Math: Writing & Solving One-Step Equations
- WEST Middle Grades Math: Writing & Solving Two-Step Equations
- WEST Middle Grades Math: Simplifying & Solving Rational Expressions
- WEST Middle Grades Math: The Coordinate Graph
- WEST Middle Grades Math: Linear Equations
- WEST Middle Grades Math: Systems of Linear Equations
- WEST Middle Grades Math: Rates, Ratios & Proportions
- WEST Middle Grades Math: Measurements
- WEST Middle Grades Math: Perimeter & Area
- WEST Middle Grades Math: Polyhedrons & Geometric Solids
- WEST Middle Grades Math: Symmetry, Similarity & Congruence
- WEST Middle Grades Math: Properties of Lines
- WEST Middle Grades Math: Angles
- WEST Middle Grades Math: Triangle Theorems & Proofs
- WEST Middle Grades Math: Similar Polygons
- WEST Middle Grades Math: The Pythagorean Theorem
- WEST Middle Grades Math: Quadrilaterals
- WEST Middle Grades Math: Circles
- WEST Middle Grades Math: Circular Arcs & Measurement
- WEST Middle Grades Math: Transformations
- WEST Middle Grades Math: Data & Graphs
- WEST Middle Grades Math: Statistics
- WEST Middle Grades Math: Data Collection
- WEST Middle Grades Math: Samples & Populations
- WEST Middle Grades Math: Probability
- WEST Middle Grades Math: Sets
- WEST Middle Grades Mathematics Flashcards