TRIG FORMULA COPIED! 📐

SINE RATIO

sin(θ) = O / H

COSINE RATIO

cos(θ) = A / H

TANGENT RATIO

tan(θ) = O / A

Trigonometry Variable Guide 📐

θ
Theta

The reference angle we are looking at. Usually measured in degrees.

O
Opposite Side

The side directly across from the angle θ. It doesn't touch the angle.

A
Adjacent Side

The side next to the angle θ that is not the hypotenuse.

H
Hypotenuse

The longest side, opposite the 90° angle. Always the same in a triangle.

sin
Sine Ratio

Calculated as Opposite divided by Hypotenuse (O/H).

cos
Cosine Ratio

Calculated as Adjacent divided by Hypotenuse (A/H).

tan
Tangent Ratio

Calculated as Opposite divided by Adjacent (O/A).

°
Degrees

The unit used to measure the rotation or size of the angle.

S-C-T
Mnemonic

The "magic word" to remember which sides go with which ratio.

sin⁻¹
Inverse Trig

Used to find the angle θ when you already know the side lengths.

=
The Ratio

The relationship between the angle and the sides remains constant.

Legacy of the Angles 📜

sinθ

190 BC | THE FIRST TABLES

Greek mathematician Hipparchus, the "Father of Trigonometry," compiled the first table of chords to calculate planetary positions and star distances.

500 AD | INDIAN GENIUS

Aryabhata and other Indian mathematicians defined the "Sine" (Jya) and "Cosine" concepts we use today, moving away from full chords to half-chords.

1748 AD | EULER'S ERA

Leonhard Euler modernized the subject by treating trig functions as ratios and linking them to complex numbers, making modern calculus possible.

"Did you know? Trigonometry was originally created for Astronomy. It was the tool used to measure the size of the Earth and the distance to the Moon!"