# Ch 39: NMTA Math: Circles & Arc of a Circle

### About This Chapter

## NMTA Math: Circles & Arc of a Circle - Chapter Summary

If you're not feeling quite ready for the NMTA Math test or you just want to convince yourself that you are, our video lessons about circles and their arcs and the associated quizzes can help you. The videos are brief but thorough and can be squeezed into short breaks throughout your day. Watch them anytime, anywhere including on mobile devices. The lessons review all you need to know about the mathematics of circles, including:

- Calculating area and circumference of circles
- Definition of central and inscribed angles
- Steps to take to measure an arc
- Theorems about circular tangents
- Calculating angles and lengths of tangents, chords and secants
- Determining the area and arc length of a sector

Be sure to take the short quizzes that follow each of the lessons so you'll know whether you're retaining the information. Then re-watch any of the videos if you need to.

### Objectives for the NMTA Math: Circles & Arc of a Circle Chapter

We know you want to do well on the NMTA Math test so we have made sure our chapter covers relevant information. The NMTA Math test is computer-based with 150 multiple-choice questions. There are 5 sections on the exam and you may encounter questions about circles on the Measurement & Geometry and Trigonometry & Calculus sections, each of which constitutes about 19% of the test.

You may find questions on the Geometry section that test your ability to solve numerical, word and real-world problems with your knowledge of perimeter, circumference, area, surface area and volume of shapes such as circles. On the Trigonometry section you may find questions assessing your ability to use trigonometric functions to solve problems involving angles and the unit circle.

Are you ready to check circles and arcs off your study list? We'd love to help.

### 1. Circles: Area and Circumference

Understanding how to calculate the area and circumference of circles plays a vital role in some of our everyday functions. They serve as the foundation for operating with three-dimensional figures. Learn more about the area and circumference of circles in this lesson.

### 2. Circular Arcs and Circles: Definitions and Examples

What is a circle? In this lesson, find out all about the circle and its many parts, including circular arcs and semicircles. Also, discover how a locus works in creating a circle, parallel lines and more.

### 3. Central and Inscribed Angles: Definitions and Examples

When we're working with circles, there are two key angles to know: central angles and inscribed angles. These angles have a few special theorems, which we'll discuss and practice using in this lesson.

### 4. Measure of an Arc: Process & Practice

What is the measure of an arc? And what is the difference between a minor arc and a major arc? Find out all that and practice finding the measure of an arc in this lesson.

### 5. How to Find the Measure of an Inscribed Angle

Finding the measure of an inscribed angle requires knowing a little information. In this lesson, we'll find the measure of an inscribed angle when we know the measure of the central angle or one or more of the arcs formed by the angle.

### 6. Tangent of a Circle: Definition & Theorems

What happens when a line just barely touches a circle? It's a tangent! In this lesson, we'll learn all about tangents to circles, including a few key theorems. We'll also look at tangent circles.

### 7. Measurements of Angles Involving Tangents, Chords & Secants

When lines and circles meet, angles are formed. Fortunately, we can determine the measure of these angles, whether they're formed by tangents, secants or chords, just by knowing the measure of the created arcs.

### 8. Measurements of Lengths Involving Tangents, Chords and Secants

The lengths of chords, tangents and secants take on unique relationships when they're drawn on circles. In this lesson, we'll define those relationships and see them in action.

### 9. Arc Length of a Sector: Definition and Area

In this lesson, we'll slice up a circle like it's a pizza and learn how to find out useful information about our slices. We'll find out the area of these sectors, or pie slices. We'll also learn about arc lengths.

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### Other Chapters

Other chapters within the NMTA Mathematics (304): 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: Triangle Theorems & Proofs
- NMTA Math: Parallel Lines & Polygons
- NMTA Math: Quadrilaterals
- 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