While the 2025 Digital SAT focuses heavily on algebra and data analysis, geometry and trigonometry still make up about 10–15% of the Math section — and those questions often decide whether you hit a top percentile score. Students who skip geometry review often lose quick points on shape properties, coordinate problems, and right-triangle relationships.
At RevisionDojo, we help SAT students learn smarter, not harder. This guide breaks down the must-know geometry and trigonometry formulas, common traps, and time-saving strategies for dominating the geometry-based questions in the 2025 SAT.
Before diving into formulas, follow this quick preparation checklist:
- Memorize all key geometry and trig formulas early — the SAT doesn’t give you a formula sheet.
- Practice visualizing problems — sketching shapes clarifies relationships.
- Review coordinate geometry daily — it’s the bridge between algebra and geometry.
- Know the difference between exact and approximate trig values.
- Use RevisionDojo’s structured SAT guides to practice geometry in real exam conditions.
By turning formulas into muscle memory, you’ll solve geometry problems in seconds, not minutes.
The SAT isn’t testing obscure theorems — it’s assessing how well you apply geometry to logical reasoning. Expect questions in these areas:
- Angles and triangles
- Circles and arcs
- Polygons and perimeter
- Area and volume
- Coordinate geometry
- Right triangles and trigonometry
If you can handle these six categories confidently, you’re equipped for 100% of geometry-based SAT questions.
- Sum of interior angles in a triangle: 180°
- Exterior angle = sum of remote interior angles
- Isosceles triangle: two equal sides → two equal angles
- Equilateral triangle: all sides and angles equal (60° each)
- Area of a triangle: A = ½bh
- Pythagorean theorem: a² + b² = c²
- Special right triangles:
- 45°–45°–90° → sides x, x, x√2
- 30°–60°–90° → sides x, x√3, 2x
- Circumference: C = 2πr
- Area: A = πr²
- Arc length: (θ / 360°) × 2πr
- Sector area: (θ / 360°) × πr²
- Equation of a circle: (x - h)² + (y - k)² = r²
- Sum of interior angles: (n - 2) × 180°
- Each interior angle (regular polygon): [(n - 2) × 180°] / n
- Perimeter = sum of side lengths
- Rectangle: A = lw
- Trapezoid: A = ½(b₁ + b₂)h
- Parallelogram: A = bh
- Circle: A = πr²
- Rectangular prism: V = lwh
- Cylinder: V = πr²h
- Cone: V = (1/3)πr²h
- Sphere: V = (4/3)πr³
- Distance formula: √[(x₂ - x₁)² + (y₂ - y₁)²]
- Midpoint: ((x₁ + x₂)/2, (y₁ + y₂)/2)
- Slope: (y₂ - y₁) / (x₂ - x₁)
- Equation of a line: y = mx + b
These formulas appear again and again — master them now, and you’ll instantly recognize problem types during the exam.
You won’t need advanced trigonometry on the SAT, but a solid grasp of basics is essential.
- sin(θ) = opposite / hypotenuse
- cos(θ) = adjacent / hypotenuse
- tan(θ) = opposite / adjacent
- sin²θ + cos²θ = 1
- tan(θ) = sin(θ) / cos(θ)
- sin(30°) = ½
- cos(30°) = √3/2
- sin(45°) = √2/2
- cos(45°) = √2/2
- sin(60°) = √3/2
- cos(60°) = ½
If you’re solving for an angle in a right triangle, use inverse functions:
- θ = sin⁻¹(opposite / hypotenuse)
- θ = tan⁻¹(opposite / adjacent)
Even if a diagram is provided, redraw it and label everything you can: angles, side lengths, and given relationships.
Why? Because many SAT geometry questions are not drawn to scale — your brain remembers visuals better when you reconstruct them.
For geometry questions involving variables, plug in simple numbers (like 3, 4, 5) that satisfy conditions.
Example:
If a triangle’s sides are in a 3:4:5 ratio, plug those values in to find area or perimeter quickly.
This method helps eliminate wrong answer choices and keeps your algebra manageable.
Whenever you see diagonals, altitude lines, or circle radii — think right triangles. The SAT loves to hide Pythagorean setups inside bigger shapes.
Recognizing them early often reveals shortcut paths to solutions.
Many geometry problems are hybrids — they require algebraic reasoning, not just geometric recall.
Example:
The equation of a circle is (x - 3)² + (y + 2)² = 25.
- The center is (3, -2)
- The radius is √25 = 5
Understanding how to translate between geometry and equations is a hallmark of top SAT scorers.
Geometry questions are often wordier but not harder. Since formulas are rarely provided, memorizing them saves up to 10–15 seconds per problem. That’s an entire question’s worth of time across the test.
At RevisionDojo, our SAT Cheatsheets are built exactly for this — quick visual recall of every tested formula, structured by topic.
- Confusing radius and diameter (especially in circle equations).
- Forgetting units — the SAT sometimes tests dimensional consistency.
- Assuming drawings are to scale.
- Using degrees instead of radians (SAT uses degrees exclusively).
- Mixing up special triangle ratios.
Keep a one-page “error tracker” where you list every formula or concept you’ve missed at least once.
- Use color-coded flashcards for triangle types and circle formulas.
- Draw diagrams by hand — spatial repetition improves recall.
- Practice backwards: Start from the answer and reconstruct how the question was built.
- Compare similar formulas (area vs. volume, circumference vs. perimeter) to avoid confusion.
These techniques make memory stick far longer than rote memorization.
1. How many geometry and trigonometry questions are on the SAT?
Usually 5–8 out of 44 math questions. They’re quick wins for students who memorize the formulas and recognize patterns early.
2. Are formulas provided on the test?
A few are, but not all. For maximum efficiency, memorize everything in this guide.
3. How can I get faster at geometry questions?
Drill formulas daily and use plug-in strategies. Time your practice to 1 minute per question.
4. What geometry topics are most important?
Triangles (especially right triangles), circles, and coordinate geometry appear most frequently.
5. How can RevisionDojo help me improve?
RevisionDojo’s SAT Cheatsheets include every geometry and trigonometry formula organized for instant recall. They turn complex visual problems into fast, structured solutions.
Geometry and trigonometry questions are some of the fastest points available on the SAT—if you know the right formulas and strategies. With consistent practice and structured review, you’ll move through these problems with precision and confidence.
RevisionDojo SAT make formula memorization simple, giving you the clarity and speed to maximize every point in the Math section.
Study smart. Visualize often. And make geometry your strength for the 2025 SAT.
