# Ch 34: GACE Math: Properties of Triangles

### About This Chapter

## GACE Math: Properties of Triangles - Chapter Summary

Watch these brief, effective videos to review the triangle property topics likely to appear on the GACE Math assessment. As you navigate the lessons, you will get demonstrations of the following:

- Triangle classifications by angle and size
- Perimeter and area measurements
- Interior and exterior triangle angles
- Median, altitude, and angle bisectors
- Concurrent lines and dilations
- The Pythagorean theorem

Use the quiz on triangle properties after each lesson to get practice with the properties you need to know. If you get stuck on a question, take a look at the lesson transcripts, which highlight important ideas. You should also feel free to ask our instructors for assistance.

### 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 GACE Mathematics (522): Practice & Study Guide course

- GACE Math: Properties of Real Numbers
- GACE Math: Fractions
- GACE Math: Decimals & Percents
- GACE Math: Ratios & Proportions
- GACE Math: Measurements & Conversions
- GACE Math: Logic
- GACE Math: Mathematical Reasoning
- GACE Math: Vector Operations
- GACE Math: Matrices & Determinants
- GACE Math: Exponents & Exponential Expressions
- GACE Math: Algebraic Expressions
- GACE Math: Linear Equations
- GACE Math: Inequalities
- GACE Math: Absolute Value Problems
- GACE Math: Quadratic Equations
- GACE Math: Polynomials
- GACE Math: Rational Expressions
- GACE Math: Radical Expressions
- GACE Math: Systems of Equations
- GACE Math: Complex Numbers
- GACE Math: Functions
- GACE Math: Piecewise Functions
- GACE Math: Exponential & Logarithmic Functions
- GACE Math: Continuity of Functions
- GACE Math: Limits
- GACE Math: Rate of Change
- GACE Math: Calculating Derivatives & Derivative Rules
- GACE Math: Graphing Derivatives
- GACE Math: Applications of Derivatives
- GACE Math: Area Under the Curve & Integrals
- GACE Math: Integration Techniques
- GACE Math: Integration Applications
- GACE Math: Introduction to Geometric Figures
- GACE Math: Triangles, Theorems & Proofs
- GACE Math: Parallel Lines & Polygons
- GACE Math: Quadrilaterals
- GACE Math: Circular Arcs & Circles
- GACE Math: Conic Sections
- GACE Math: Geometric Solids
- GACE Math: Analytical Geometry
- GACE Math: Using Trigonometric Functions
- GACE Math: Trigonometric Graphs
- GACE Math: Solving Trigonometric Equations
- GACE Math: Trigonometric Identities
- GACE Math: Sequences & Series
- GACE Math: Graph Theory
- GACE Math: Set Theory
- GACE Math: Overview of Statistics
- GACE Math: Summarizing Data
- GACE Math: Tables & Plots
- GACE Math: Probability
- GACE Math: Discrete Probability Distributions
- GACE Math: Continuous Probability Distributions
- GACE Math: Sampling
- GACE Math: Regression & Correlation
- GACE Mathematics Flashcards