# Ch 36: NMTA Math: Triangle Theorems & Proofs

### About This Chapter

## NMTA Math: Triangle Theorems & Proofs - Chapter Summary

If you're preparing to take the NMTA Math certification assessment, watch these videos to study the triangle theorems and proofs you'll likely be tested on. Lesson topics include:

- The SAS, ASA and SSS triangle congruence postulates
- Congruence proofs and converse of a statement
- Using congruence and similarity to prove relationships
- The AAS, HA and HL theorems
- The perpendicular bisector and angle bisector theorems
- Congruency in right and isosceles triangles

Lesson quizzes let you practice working through the proofs and help you retain the information from the videos. Use the lesson transcripts to track down key ideas for additional review.

### Objectives of the NMTA Math: Triangle Theorems & Proofs Chapter

Use the videos and quizzes in this chapter to master triangle proofs and theorems ahead of your NMTA Math certification assessment. The computer-administered exam includes 150 multiple-choice questions covering five content areas: calculus and trig; math processes and number sense; measurement and geometry; stats, probability and discrete math; and patterns, algebra and functions. The topics of this chapter can be found within the measurement and geometry section, which makes up 19% of the test questions. You'll be allowed four and a quarter hours to complete the assessment.

### 1. 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.

### 2. Congruence Proofs: Corresponding Parts of Congruent Triangles

Congruent triangles have congruent sides and angles, and the sides and angles of one triangle correspond to their twins in the other. In this lesson, we'll try practice with some geometric proofs based around this theorem.

### 3. Converse of a Statement: Explanation and Example

Just because a conditional statement is true, is the converse of the statement always going to be true? In this lesson, we'll learn the truth about the converse of statements.

### 4. Practice Proving Relationships using Congruence & Similarity

In geometry, if two shapes are similar they have the same shape but different sizes, while two congruent shapes have the same shape and size. In this lesson, you will learn how to prove that shapes are similar or congruent.

### 5. 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.

### 6. The HA (Hypotenuse Angle) Theorem: Proof, Explanation, & Examples

In this lesson, we'll learn about the hypotenuse angle theorem. With this theorem, we can prove two right triangles are congruent with just congruent hypotenuses and acute angles.

### 7. The HL (Hypotenuse Leg) Theorem: Definition, Proof, & Examples

In this lesson, we'll learn about the hypotenuse leg theorem. This theorem enables us to prove two right triangles are congruent based on just two sides.

### 8. Perpendicular Bisector Theorem: Proof and Example

Perpendicular bisectors are multifunctional lines. They're not only perpendicular to the line in question, they also neatly divide it into two equal halves. In this lesson, we'll learn about the perpendicular bisector theorem.

### 9. Angle Bisector Theorem: Proof and Example

The angle bisector theorem sounds almost too good to be true. In this lesson, we set out to prove the theorem and then look at a few examples of how it's used.

### 10. Congruency of Right Triangles: Definition of LA and LL Theorems

In this lesson, we'll learn two theorems that help us prove when two right triangles are congruent to one another. The LA theorem, or leg-acute, and LL theorem, or leg-leg, are useful shortcuts for proving congruence.

### 11. Congruency of Isosceles Triangles: Proving the Theorem

Isosceles triangles have two equal sides. Are the base angles also equal? In this lesson, we'll prove how this is true. We'll also prove the theorem's converse.

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### Other Chapters

Other chapters within the NMTA Mathematics: Practice & Study Guide course

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