θ
Theta Symbol (θ)
Theta (θ) is a Greek letter used in mathematics, geometry, and physics as a standard variable representing an unknown angle.
Trigonometry Definition & Usage
Angle Variable
Just as $x$ and $y$ are standard variables for numbers, $\theta$ is the standard placeholder for an angle. It is widely used in right-triangle trigonometry ratios, polar coordinates, and rotation kinematics.
Example Formula
The basic trigonometric sine ratio for an angle $\theta$ is:
\sin(\theta) = \frac{\text{opposite}}{\text{hypotenuse}}