Values at 30, 45 and 60 Degrees — Cheat sheet

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All six, at all three angles

30∘30^\circ45∘45^\circ60∘60^\circ
sin⁡\sin12\dfrac{1}{2}12\dfrac{1}{\sqrt{2}}32\dfrac{\sqrt{3}}{2}
cos⁡\cos32\dfrac{\sqrt{3}}{2}12\dfrac{1}{\sqrt{2}}12\dfrac{1}{2}
tan⁡\tan13\dfrac{1}{\sqrt{3}}113\sqrt{3}
cot⁡\cot3\sqrt{3}1113\dfrac{1}{\sqrt{3}}
sec⁡\sec23\dfrac{2}{\sqrt{3}}2\sqrt{2}22
csc⁡\csc222\sqrt{2}23\dfrac{2}{\sqrt{3}}

In radians

Degrees30∘30^\circ45∘45^\circ60∘60^\circ
Radiansπ6\dfrac{\pi}{6}π4\dfrac{\pi}{4}π3\dfrac{\pi}{3}

Half a turn is π=180∘\pi = 180^\circ.

Rebuild it from two triangles

TriangleFromSides
30-60-90half an equilateral triangle of side 2x2xxx, x3x\sqrt{3}, 2x2x
45-45-90a square of side xx cut along its diagonalxx, xx, x2x\sqrt{2}

The xx cancels in every ratio. That is why the size of the triangle never matters.

Patterns

PatternWhy
The 30∘30^\circ and 60∘60^\circ columns are each other reversedthe two angles add to 90∘90^\circ
sin⁡45∘=cos⁡45∘\sin 45^\circ = \cos 45^\circthat triangle is isosceles
13\dfrac{1}{\sqrt{3}} is also written 33\dfrac{\sqrt{3}}{3}some books clear the root from the bottom
Learn the radians toocalculus never asks in degrees