Trigonometry Ratios Table

Exact values for sin, cos and tan at standard angles (0°, 30°, 45°, 60°, 90°) and beyond. Features an interactive unit circle, real-time angle calculator, √0–√4 memory pattern, and SOHCAHTOA rules.

ESSENTIAL EXACT VALUES (0° – 90°)

Angle (θ) Radians sin θ cos θ tan θ
0° 0 0 1 0
30° π/6 1/2 √3 / 2 1/√3
45° π/4 √2 / 2 √2 / 2 1
60° π/3 √3 / 2 1/2 √3
90° π/2 1 0 —

Click any row to inspect it on the unit circle →

REAL-TIME ANGLE CALCULATOR

degrees

THE √0 → √4 MEMORY TRICK

For sin θ, count from 0 to 4, take the square root, and divide by 2:

0° sin = √0 / 2 = 0
30° sin = √1 / 2 = 1/2
45° sin = √2 / 2 = √2 / 2
60° sin = √3 / 2 = √3 / 2
90° sin = √4 / 2 = 1

cos θ is simply sin in reverse order: cos 0° = √4/2 = 1, cos 90° = √0/2 = 0.

INTERACTIVE UNIT CIRCLE

x y O 0° 30° 45° 60° 90° 120° 135° 150° 180° 270°
cos θ (x-coord) sin θ (y-coord)

SOHCAHTOA DEFINITIONS

SOH Sin θ = Opposite / Hypotenuse
CAH Cos θ = Adjacent / Hypotenuse
TOA Tan θ = Opposite / Adjacent

Key identities: tan θ = sin θ / cos θ  ·  sin²θ + cos²θ = 1

WHY 30°, 45° AND 60°?

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Equilateral Triangle (30°, 60°)

Bisect an equilateral triangle of side length 2. The base splits to 1, and Pythagoras gives a height of √3. Thus sin 30° = 1/2 and sin 60° = √3/2 exactly.

◻

Isosceles Right Triangle (45°)

A square of side 1 cut diagonally has a hypotenuse of √2. Thus sin 45° = cos 45° = 1/√2 = √2/2 exactly.

All Standard Angles (0° to 360°)

Click any row to view on unit circle

Angle Radians sin θ cos θ tan θ sin (decimal) cos (decimal)
0° 0 0 1 0 0.0000 1.0000
30° π/6 1/2 √3 / 2 1/√3 0.5000 0.8660
45° π/4 √2 / 2 √2 / 2 1 0.7071 0.7071
60° π/3 √3 / 2 1/2 √3 0.8660 0.5000
90° π/2 1 0 — 1.0000 0.0000
120° 2π/3 √3 / 2 −1/2 −√3 0.8660 -0.5000
135° 3π/4 √2 / 2 −√2 / 2 −1 0.7071 -0.7071
150° 5π/6 1/2 −√3 / 2 −1/√3 0.5000 -0.8660
180° π 0 −1 0 0.0000 -1.0000
210° 7π/6 −1/2 −√3 / 2 1/√3 -0.5000 -0.8660
225° 5π/4 −√2 / 2 −√2 / 2 1 -0.7071 -0.7071
240° 4π/3 −√3 / 2 −1/2 √3 -0.8660 -0.5000
270° 3π/2 −1 0 — -1.0000 0.0000
300° 5π/3 −√3 / 2 1/2 −√3 -0.8660 0.5000
315° 7π/4 −√2 / 2 √2 / 2 −1 -0.7071 0.7071
330° 11π/6 −1/2 √3 / 2 −1/√3 -0.5000 0.8660
360° 2π 0 1 0 0.0000 1.0000

Highlighted rows indicate standard exact values essential for secondary school & A-level exams.