Module 3 · Advanced Algebra
Chapter 16: Rational Expressions
Advanced Math
6 topics
What this chapter covers
The 6 topics below make up Rational Expressions on the Digital SAT. Click any topic to open its notes, examples and practice test.
Study material & tests
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Formula Reference Sheet
This chapter
Operations
| Simplify | factor top and bottom, cancel common factors |
|---|---|
| Multiply | (a/b)(c/d) = ac/bd |
| Divide | (a/b) ÷ (c/d) = (a/b)(d/c) |
| Add/subtract | use a common denominator |
Cautions
| Restrictions | denominator ≠ 0 (exclude those x) |
|---|---|
| Solve equations | clear denominators, then solve |
| Check | reject answers that make a denominator 0 |
Digital SAT reference
Area & Circumference
| Circle area | A = πr² |
|---|---|
| Circle circumference | C = 2πr |
| Rectangle | A = ℓw |
| Triangle | A = ½ b h |
Volume
| Rectangular box | V = ℓwh |
|---|---|
| Cylinder | V = πr²h |
| Sphere | V = 4⁄3 πr³ |
| Cone | V = 1⁄3 πr²h |
| Pyramid | V = 1⁄3 ℓwh |
Right triangles
| Pythagorean theorem | a² + b² = c² |
|---|---|
| 30°–60°–90° | sides x : x√3 : 2x |
| 45°–45°–90° | sides s : s : s√2 |
Constants
| Degrees in a circle | 360° |
|---|---|
| Radians in a circle | 2π |
| Angles of a triangle | sum = 180° |
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