# Ch 23: Compass Math: Circles

### About This Chapter

## Compass Math: Circles - Chapter Summary

This chapter presents several quick, convenient, engaging videos on the mathematics of circles to help you prepare for your Compass Math placement test. As you navigate the videos, you will examine:

- Properties of circles
- Using pi to calculate circumference
- Finding the diameter of a circle with pi
- Inscribed angles and central angles
- Circumscribed and inscribed figures

Following each video, you'll find a short quiz that lets you practice answering geometry-focused questions about circles and assess your understanding of the material. If you get stuck on a question or confused by a video, ask our instructors for assistance.

### Objectives of the Compass Math: Circles Chapter

We've assembled this short series to refresh your memory of the geometry of circles to help you prepare for your Compass Math exam. Your school will use your Compass results to place you in a level-appropriate mathematics course. There are five sections to the Compass Math exam, and the Geometry Placement Test contains questions about circles.

The test is computerized and adjusts the difficulty level of the questions it presents to you based on your performance over the exam. The more questions you answer correctly, the more difficult the questions will become. All questions are multiple choice, and you'll have as long as you need to complete the assessment.

### 1. Properties of Shapes: Circles

Circles are fundamental to everything we do. But, did you know they're much more than just round shapes? In this lesson, we'll look at the various parts of circles and how they all relate.

### 2. Diameter and Circumference Related with Pi

After watching this video, you will be able to tell others how the number pi is related to a circle's diameter and circumference. And using your newfound knowledge, you will be able to calculate the circumference or diameter of a circle.

### 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. Inscribed and Circumscribed Figures: Definition & Construction

A square and a circle may be different shapes, but they still can have a unique relationship. In this lesson, we'll learn about inscribed and circumscribed figures.

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### Other Chapters

Other chapters within the ACT Compass Math Test: Practice & Study Guide course

- Compass Math: Integers
- Compass Math: Decimals
- Compass Math: Fractions
- Compass Math: Exponents
- Compass Math: Roots & Radicals
- Compass Math: Percents
- Compass Math: Ratios, Rates & Proportions
- Compass Math: Median, Mean & Mode
- Compass Math: Algebraic Equations & Expressions
- Compass Math: Linear Equations
- Compass Math: Substituting Values
- Compass Math: Monomials & Polynomials
- Compass Math: Factoring Polynomials
- Compass Math: Matrices & Absolute Value
- Compass Math: Inequalities
- Compass Math: Complex Numbers
- Compass Math: Logarithms
- Compass Math: Basic Geometry
- Compass Math: Lines & Angles
- Compass Math: Polygons
- Compass Math: Triangles
- Compass Math: Quadrilaterals
- Compass Math: Similar Figures
- Compass Math: Complex Figures
- Compass Math: Constructions
- Compass Math: Area, Circumference & Perimeter
- Compass Math: Mathematical Modeling
- Compass Math: Quadratics
- Compass Math: Quadratic Functions
- Compass Math: Trigonometric Functions
- Compass Math: Rational Functions
- Compass Math: Function Operations
- Compass Math: Trigonometric Identities
- Compass Math: Trigonometric Equations
- Compass Math: Trigonometric Applications
- Compass Math: Trigonometric Graphs
- Compass Math: Graph Symmetry
- Compass Math: Polar Coordinates & Parameterization