# Ch 42: ORELA Middle Grades Math: Triangles

### About This Chapter

## ORELA Middle Grades Math: Triangles - Chapter Summary

This chapter can help you review the properties and classifications of triangles in preparation for ORELA Middle Grades Math teacher certification exam. The video lessons in this chapter address topics such as:

- Properties of triangles
- Classifying triangles
- Interior and exterior angles
- Identifying similar triangles
- Constructing medians
- Median and altitudes
- Geometric constructions
- Concurrent line properties

The videos in this chapter are taught by experienced instructors who use entertaining graphics and examples that make this review both easy and fun. The videos include embedded tags so you can skip to the areas that may need an extra look, and each lesson concludes with a short multiple-choice quiz that allows you to test your comprehension.

### ORELA Middle Grades Math: Triangles Chapter Objectives

The state of Oregon has replaced this ORELA exam with an NES Middle Grades Math exam. This test is designed to assess not only your math knowledge in a number of areas but also your teaching abilities. The material covered in this chapter on triangles is from the measurement and geometry domain area, which makes up approximately one-quarter of the test.

This is a computer-based test that includes 150 multiple-choice questions; it has a four-hour-and-fifteen-minute time limit. The videos and self-assessment quizzes in this Triangles chapter can not only help you review topics that you may encounter on the test, but also permit you to become comfortable with the format of the computer-based questions.

### 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 ORELA Middle Grades Mathematics: Practice & Study Guide course

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