SAT Math · 15% of section

Geometry and TrigonometrySAT Math Prep

Master Geometry and Trigonometry with 272+ adaptive practice questions. This domain makes up 15% of the SAT Math section (5–7 questions on test day).

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Skills Covered

Area & VolumeAreas of 2D figures and volumes of 3D solids, including composite shapes and problems where scaling changes area or volume.Lines, Angles & TrianglesParallel-line angle relationships, triangle angle sums, similarity and congruence, and the triangle inequality.Right Triangles & TrigonometryThe Pythagorean theorem, special right triangles, and SOH-CAH-TOA trigonometric ratios, including the sine-cosine complement relationship.CirclesCircle equations in the xy-plane, arc length, sector area, central angles, and completing the square to find center and radius.

At a Glance

272+

Questions

15%

of Math

5–7

Qs on test day

3

Difficulty levels

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Study Strategies for Geometry and Trigonometry

Memorize the reference sheet, then forget it exists

The Digital SAT provides a reference sheet with area, volume, and special right triangle formulas. Memorize these formulas so thoroughly that you never need to open the reference during the test. Every time you stop to look up a formula, you lose 10–15 seconds of focus. The formulas you need most are: area of a circle (πr²), Pythagorean theorem, and special right triangle ratios (30-60-90 and 45-45-90).

Draw and label diagrams

When a Geometry question describes a figure without providing one, sketch it yourself. Label every measurement given in the problem. Many students try to solve geometry questions abstractly and miss relationships that become obvious in a diagram. Even when a figure is provided, adding the given measurements to it helps you see the path to the solution.

Use right triangles as your primary tool

A surprising number of geometry and trigonometry questions can be solved by identifying or creating a right triangle within the figure. Drop altitudes, draw diagonals, and look for special right triangles. Once you have a right triangle, you can apply the Pythagorean theorem, SOH-CAH-TOA, or special ratios to find missing lengths and angles.

Convert between degrees and radians fluently

Trigonometry questions may use either degrees or radians, and the SAT expects you to move between them without hesitation. Remember that π radians = 180°. Practice converting common angles (30° = π/6, 45° = π/4, 60° = π/3, 90° = π/2) until the conversions are instant. This fluency saves time on every trig question.

Common Mistakes to Avoid

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Using diameter instead of radius (or vice versa)

Circle problems are the number-one source of careless errors. Always confirm whether the problem gives you the radius or the diameter, and convert if necessary before applying formulas.

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Assuming figures are drawn to scale

The Digital SAT states that figures are not necessarily drawn to scale. Never estimate angle measures or lengths from the diagram—use the given information and geometric relationships instead.

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Forgetting to convert units

Some problems mix units (inches and feet, seconds and minutes). Before calculating, convert all measurements to the same unit. Missing a unit conversion is an easy way to lose points on otherwise simple problems.

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Applying trig ratios to non-right triangles

SOH-CAH-TOA only applies to right triangles. If the triangle is not a right triangle, you need the Law of Sines or Law of Cosines. Always check for the right angle before setting up a trig ratio.

Frequently Asked Questions

How much trigonometry is on the Digital SAT?+
Trigonometry makes up a small but consistent portion of the Geometry and Trigonometry domain, which itself represents about 15% of the Math section. You can expect 2–4 trig questions per test. The main topics are right triangle trigonometry (SOH-CAH-TOA), the unit circle, radian measure, and basic trig identities. You do not need to know the Law of Sines or Law of Cosines in depth.
What geometry formulas do I need to memorize?+
While the SAT provides a reference sheet, you should memorize the most common formulas to save time: area of a triangle (½bh), area of a circle (πr²), circumference (2πr), Pythagorean theorem (a² + b² = c²), volume of a rectangular prism (lwh), and the special right triangle ratios (45-45-90: 1:1:√2 and 30-60-90: 1:√3:2). These cover the majority of geometry questions.
How do I approach circle equation questions?+
Circle equations on the SAT use the standard form (x − h)² + (y − k)² = r², where (h, k) is the center and r is the radius. If the equation is given in general form (x² + y² + Dx + Ey + F = 0), you need to complete the square to convert it. Practice completing the square for both x and y terms until the process is automatic. These questions are very formulaic and become easy with practice.

Explore Other SAT Domains

Information and Ideas26%Craft and Structure28%Expression of Ideas20%Standard English Conventions26%Algebra35%Advanced Math35%Problem-Solving & Data Analysis15%

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Geometry and TrigonometryQuestion 1 of 1,804

In a circle, a central angle measures 80°. An inscribed angle intercepts the same arc. What is the measure of the inscribed angle, in degrees?

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