SAT Math / Topic
Geometry and Trigonometry
Geometry and Trigonometry is about 15% of SAT Math: angle relationships, triangles and similarity, circles, area and volume, coordinate geometry, and right-triangle trig. A reference sheet of common formulas is provided, but speed comes from knowing them cold.
What the exam asks
- Use angle relationships from parallel lines, triangles, and polygons
- Apply the Pythagorean theorem and recognize special right triangles
- Work with similar triangles and scale factors for lengths and areas
- Compute arc length, sector area, and interpret circle equations
- Solve right triangles with sine, cosine, and tangent
- Use distance, midpoint, and slope in the coordinate plane
Key formulas and rules
a² + b² = c²
45-45-90: x, x, x√2; 30-60-90: x, x√3, 2x
sin = opp/hyp, cos = adj/hyp, tan = opp/adj
sin(x) = cos(90° − x)
(x − h)² + (y − k)² = r², center (h, k), radius r
arc = (θ/360)·2πr, sector = (θ/360)·πr²
interior angles sum to 180°; exterior angle = sum of remote interior angles
Question bank breakdown
53
15 easy · 19 medium · 19 hard
Skills covered
Every question in the bank comes with a per-choice explanation, so you learn why each wrong answer is wrong — not just the key.
Practice this topic
The full set of Geometry and Trigonometry questions — with a per-choice explanation on every answer — lives in the practice workspace. Start free, no account needed.
Study tip
Similar-triangle questions hide in wordy setups (shadows, ramps, nested triangles). The moment two triangles share two angles, set up a side ratio — that single move solves most SAT geometry word problems.