# Ch 14: ISTEP+ Grade 7 Math: Triangles

### About This Chapter

## ISTEP+ Grade 7 Math: Triangles - Chapter Summary

These lessons will help students review the parts, properties and theorems of triangles; thus, improving their skills solving mathematical problems with triangles. In them our expert instructors will help your student(s) prepare for questions on the Indiana Statewide Testing for Educational Progress Plus (ISTEP+) Grade 7 Mathematics exam that may ask about:

- The definition and properties of triangles
- Characteristics of equilateral, isosceles, scalene and right triangles
- Theorems and proofs of right triangles
- Using the properties of interior and exterior angles to solve problems
- Functions of medians, altitudes and angle bisectors of triangles
- SAS, ASA and SSS triangle congruence postulates
- Determining if triangles are congruent using the AAS theorem

After these lessons, have your student(s) take the lesson quizzes to discover topics from the lessons they don't understand. To help them improve their understanding of these topics, students may use the video tags to return to and study the parts of the lessons that explained them. Once a student has completed all the lessons and quizzes of this chapter, they can then test their overall understanding of the material presented in these lessons with the practice chapter exam.

### 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. 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.

### 4. 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.

### 5. Measuring the Angles of Triangles: 180 Degrees

Watch this video lesson to see why a triangle's angles always add up to 180 degrees. Also, learn how you can use this unique fact about triangles to find an unknown angle in a triangle.

### 6. 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.

### 7. Triangle Congruence Postulates: SAS, ASA & SSS

When we have two triangles, how can we tell if they're congruent? They may look the same, but you can be certain by using one of several triangle congruence postulates, such as SSS, SAS or ASA.

### 8. The AAS (Angle-Angle-Side) Theorem: Proof and Examples

When trying to find out if triangles are congruent, it's helpful to have as many tools as possible. In this lesson, we'll add to our congruence toolbox by learning about the AAS theorem, or angle-angle-side.

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### Other Chapters

Other chapters within the ISTEP+ Grade 7 - Math: Test Prep & Practice course

- ISTEP+ Grade 7 Math: Prime Factorization
- ISTEP+ Grade 7 Math: Square Roots
- ISTEP+ Grade 7 Math: Rational & Irrational Numbers
- ISTEP+ Grade 7 Math: Operations with Rational Numbers
- ISTEP+ Grade 7 Math: Math Properties
- ISTEP+ Grade 7 Math: Algebraic Expressions
- ISTEP+ Grade 7 Math: Graphing Basics
- ISTEP+ Grade 7 Math: Linear Equations
- ISTEP+ Grade 7 Math: Inequalities
- ISTEP+ Grade 7 Math: Slope & Rate of Change
- ISTEP+ Grade 7 Math: Ratios & Proportions
- ISTEP+ Grade 7 Math: Lines & Angles
- ISTEP+ Grade 7 Math: Geometric Constructions
- ISTEP+ Grade 7 Math: Similar Figures
- ISTEP+ Grade 7 Math: Area & Circumference
- ISTEP+ Grade 7 Math: Complex Figures
- ISTEP+ Grade 7 Math: Populations & Statistics
- ISTEP+ Grade 7 Math: Data Analysis & Statistics
- ISTEP+ Grade 7 Math: Probability
- ISTEP+ Grade 7 Math: Mathematical Process
- ISTEP+ Grade 7 - Math Flashcards