SAT Math · Study & Practice
Exponential Growth and Decay
Many real quantities change by a fixed percentage each period — populations, investments, radioactive material. This chapter covers growth and decay models, population and financial applications, and reading a model’s rate. Read each topic, work the problems with the hint ladder, then take the 8-question topic test.
Topics
1
Growth Models
Start →
2
Decay Models
Start →
3
Population Models
Start →
4
Financial Applications
Start →
Chapter test
Formula Reference Sheet
This chapter
Models
| Growth | A = P(1 + r)^t |
|---|---|
| Decay | A = P(1 − r)^t |
| r as decimal | r% means r ÷ 100 |
Reading a model
| Growth base | (1 + r) > 1 |
|---|---|
| Decay base | (1 − r) between 0 and 1 |
| P | the starting amount (at t = 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° |
🖩 Graphing Calculator