Grade 12 · Level 90 · Abstract & formal reasoning
MATH 90
The terminal course.
Meridian Note
The terminal course. Trigonometry synthesizes right-triangle work with functions and the unit circle (KS-9); statistical inference is KS-8 reasoning about evidence itself. The exit examination is cumulative, largely unannounced in coverage, and weighted toward transfer — because MATH 100 will assume KS-5 retention of the entire sequence.
The Fix Registry
Skills of This Course
Every skill is pinned to the meridian by fix notation — where along the scale, and at what depth. The highlighted state is this course's target: the state an honest instrument must certify before the skill counts as covered here.
| Skill | Fixes | Target at Level 90 |
|---|---|---|
| Trigonometric functions & the unit circle | 90-KS7100-KS9 | KS-7Applied |
| Pythagorean Theorem | 75-KS785-KS890-KS9 | KS-9Synthesized |
| Exponential & logarithmic functions | 88-KS690-KS7 | KS-7Applied |
| Probability | 90-KS7100-KS8 | KS-7Applied |
| Statistical inference | 90-KS7 | KS-7Applied |
Course of Instruction
Units
Unit 1.The Unit Circle: Where Triangles Become Functions
14 practice itemsIn Grade 10, sine and cosine were ratios of sides in a right triangle — useful, but trapped between 0° and 90°, because a right triangle cannot hold an angle any larger. This year those same words are given a bigger definition, built on a circle instead of a triangle, and suddenly sine and cosine accept *any* angle: 200°, −45°, ten full turns. That upgrade is what turns them from measurement tricks into genuine functions — and functions can model tides, sound waves, daylight hours, and anything else that repeats. The old right-triangle theorem you have carried since Grade 8, the Pythagorean Theorem, does not retire here; it becomes the engine inside the new machine.
MatchingMultiple choiceFill in the blankMultiple choice (misconception distractors)Problem solving
Unit 2.Sinusoidal Functions: Modeling the Repeating World
8 practice itemsWatch only the height of a point traveling around the unit circle and you get a wave: rising, cresting, falling, bottoming out, and rising again — forever. Graphed, that wave is y = sin x, and it is the mathematical signature of everything that cycles: tides, heartbeats, alternating current, the hours of daylight across a year. This unit is about reading and writing that signature. By the end you will look at a Ferris wheel or a tide chart and see four numbers — midline, amplitude, period, starting point — waiting to be turned into a formula.
MatchingMultiple choiceFill in the blankMultiple choice (misconception distractors)Problem solving
Unit 3.Exponentials and Logarithms: The Mathematics of Growth
7 practice itemsYou met exponential and logarithmic functions in MATH 88. This year they must reach KS-7: recognizing and wielding them in problems that never announce themselves — a car losing value, a bacterial culture doubling, an investment compounding, a medication level fading. The common thread is change by *multiplication* rather than addition, and the logarithm is the tool that answers the question multiplication-based growth always raises: *how long until…?*
Multiple choiceFill in the blankMultiple choice (misconception distractors)Problem solvingTransfer problem
Unit 4.Probability: Measuring Uncertainty Honestly
7 practice itemsProbability is the arithmetic of uncertainty: it assigns numbers to statements like "it will rain" or "this test result is a false alarm," and then holds those numbers to strict rules. The rules matter because human intuition about chance is famously bad — casinos, lotteries, and misleading headlines are all funded by that badness. This unit gives you the four tools college statistics will assume you own: counting probabilities correctly, multiplying them only when you have earned the right, reversing conditional questions without fooling yourself, and pricing an uncertain future with expected value.
Multiple choiceFill in the blankMultiple choice (misconception distractors)Problem solvingTransfer problem
Unit 5.Statistical Inference: Reasoning About Evidence
8 practice itemsStatistics asks the question underneath every poll, every medical study, and every 'research shows' headline: what can a limited sample honestly tell us about the whole world, and how sure are we allowed to be? Inference is not a bag of formulas — it is a discipline of reasoning about evidence, and it runs on three ideas: samples wobble by pure chance, so an interesting-looking result must first outcompete the boring explanation 'it's just chance'; our confidence should be stated as a range, not a single number; and a pattern in data, however strong, is not yet a cause. Master these and you can read the news like a scientist. This is the reasoning MATH 100 and every college lab course will assume you have.
MatchingMultiple choiceFill in the blankMultiple choice (misconception distractors)Short answer