Non-Right-Angled Triangle
Pythagorean Theorem
Find Unknown Side of a Right-Angled Triangle
Enter two known sides. Leave the unknown side blank. The theorem states $a^2 + b^2 = c^2$, where $c$ is the hypotenuse.
Trigonometric Ratios (SOH CAH TOA)
For an acute angle $\theta$ in a right-angled triangle:
- Sine ($\sin \theta$): $\frac{\text{Opposite}}{\text{Hypotenuse}}$ (SOH)
- Cosine ($\cos \theta$): $\frac{\text{Adjacent}}{\text{Hypotenuse}}$ (CAH)
- Tangent ($\tan \theta$): $\frac{\text{Opposite}}{\text{Adjacent}}$ (TOA)
Evaluate $\sin, \cos, \tan$
Reciprocal Trigonometric Ratios
- Cosecant ($\csc \theta$): $\frac{1}{\sin \theta} = \frac{\text{Hypotenuse}}{\text{Opposite}}$
- Secant ($\sec \theta$): $\frac{1}{\cos \theta} = \frac{\text{Hypotenuse}}{\text{Adjacent}}$
- Cotangent ($\cot \theta$): $\frac{1}{\tan \theta} = \frac{\text{Adjacent}}{\text{Opposite}}$
Evaluate $\csc, \sec, \cot$
Common Angle Ratios (Exact Values)
Angle ($\theta$) | $\sin \theta$ | $\cos \theta$ | $\tan \theta$ |
---|---|---|---|
$0^\circ (0 \text{ rad})$ | $0$ | $1$ | $0$ |
$30^\circ (\pi/6 \text{ rad})$ | $\frac{1}{2}$ | $\frac{\sqrt{3}}{2}$ | $\frac{1}{\sqrt{3}}$ or $\frac{\sqrt{3}}{3}$ |
$45^\circ (\pi/4 \text{ rad})$ | $\frac{1}{\sqrt{2}}$ or $\frac{\sqrt{2}}{2}$ | $\frac{1}{\sqrt{2}}$ or $\frac{\sqrt{2}}{2}$ | $1$ |
$60^\circ (\pi/3 \text{ rad})$ | $\frac{\sqrt{3}}{2}$ | $\frac{1}{2}$ | $\sqrt{3}$ |
$90^\circ (\pi/2 \text{ rad})$ | $1$ | $0$ | Undefined |
Solve Right-Angled Triangle
Find Unknown Sides and Angles
Provide exactly two pieces of information, including at least one positive side length. Angle C is assumed to be $90^\circ$.
Angles of Elevation and Depression
Angle of Elevation: The angle measured upwards from the horizontal line of sight to an object above the observer.
Angle of Depression: The angle measured downwards from the horizontal line of sight to an object below the observer.
Elevation/Depression Problem Solver
Given the height of an object and the angle of elevation to its top from the ground, find the horizontal distance.
Trigonometric Approximations for Small Angles
For small angles $\theta$ (measured in radians):
- $\sin \theta \approx \theta$
- $\cos \theta \approx 1 - \frac{\theta^2}{2}$
- $\tan \theta \approx \theta$
These approximations are useful in physics and engineering for simplifying complex equations under certain conditions.