Overview
This lecture covers all essential SAT Math concepts, strategies, and formulas, organized by increasing difficulty, from basic algebra to advanced geometry and statistics.
Algebra, Functions, and Linear Equations
- Isolate variables and apply the order of operations (PEMDAS/BIDMAS).
- Linear functions have the form y = mx + b, where m is the slope and b is the y-intercept.
- Slope is the rate of change: (change in y) / (change in x).
- Use Desmos to solve single-variable equations quickly.
- Given two points, find the slope and use one point to solve for the y-intercept.
Variables, Systems, and Exponents
- Variables change; constants do not; coefficients multiply variables.
- Systems of equations are sets of constraints—solutions are points where equations intersect.
- Parallel lines have equal slopes; perpendicular lines have negative reciprocal slopes.
- Translate word problems into equations (e.g., "is" means "=", "of" means multiply).
- Memorize exponent rules for operations with powers.
Geometry Basics
- Right angles sum to 90°, straight lines to 180°, circles to 360°.
- Vertical angles and alternate interior angles are congruent.
- Triangle angles sum to 180°; quadrilaterals to 360°.
- Pythagorean theorem for missing side lengths in right triangles.
- Know density = mass/volume.
- Isosceles triangles have two equal sides; equilateral have three.
- Perimeter = sum of sides; area and volume formulas are given on the SAT.
Statistics Fundamentals
- Mean = sum of values / count; median = middle value in a set.
- Range = maximum - minimum.
- Mean is affected by outliers; median is not.
- Use the mean to find the total by rearranging the formula.
Intermediate Concepts: Integers, Percentages, and Circles
- Integers include positive, negative whole numbers, and zero.
- Translating/reflecting functions: horizontal and vertical shifts.
- 20% of x is 0.2x; increasing x by 20% is 1.2x; decreasing is 0.8x.
- Circle equation: (x - h)² + (y - k)² = r².
- Arc length/sector area: find the fraction of the circle corresponding to the angle.
- Inscribed angle is half the central angle.
- Convert degrees to radians: 180° = π radians.
Triangles, Probability, and Data Interpretation
- Congruent triangles: identical in form; similar triangles: same angles, proportional sides.
- Prove triangle similarity using AA, SSS, or SAS (not SSA).
- Conditional probability considers subsets based on given information.
- Box plots show minimum, 25th, median, 75th, and maximum percentiles.
- For unbiased sampling, use random, representative samples.
- Quadratic functions: use Desmos for solutions and vertex.
Quadratics, Polynomials, and Exponentials
- Standard quadratic form: ax² + bx + c; vertex form: a(x-h)² + k.
- Vertex x-coordinate: h = -b/(2a).
- The sum of roots: -b/a; product: c/a.
- Exponential growth: a * r^t for repeated multiplication.
- In polynomials, odd-powered roots cross the x-axis; even-powered roots bounce.
Advanced Geometry and Statistics
- Sine of one angle equals cosine of its complement.
- When converting area or volume units, raise the conversion factor to the appropriate power (e.g., square for area).
- Doubling side length quadruples area, octuples volume.
- Surface area problems may require setting up custom equations.
Higher-Level Topics and Strategies
- The altitude from a right angle in a triangle divides it into two similar triangles.
- For problems with unknown constants, compare to quadratic standard form and solve for relationships.
- For pyramid surface area, distinguish between slant height and vertical height—use the Pythagorean theorem.
- Memorize the quadratic formula and discriminant.
- Triangle inequality: sum of any two sides > third side.
- Practice hardest problem types and review mistakes for improvement.
Key Terms & Definitions
- Variable — A symbol representing a changeable value.
- Constant — A fixed value in an equation.
- Coefficient — A number multiplying a variable.
- Mean — Average of a set.
- Median — Middle value of a data set.
- Range — Difference between max and min.
- System of equations — Set of simultaneous equations.
- Vertex — Turning point of a parabola or highest/lowest point.
- Congruent triangles — Triangles identical in shape and size.
- Similar triangles — Triangles with proportional sides and equal angles.
- Exponent — The power to which a number is raised.
Action Items / Next Steps
- Complete algebra, geometry, and exponent drills (referenced in the video description).
- Practice systems of equations, translation, and similarity proofs.
- Memorize essential formulas (circle equation, vertex formula, exponent rules).
- Use Desmos for checking and practicing graph-based problems.
- Review the most challenging problems in each topic and revisit previous errors.