# Triangle Identities

### You might like to read our page on Trigonometry first!

## Triangle Identities

The **triangle identities** are equations that are true for all triangles (they don't need to have a right angle). For the identities involving right angles triangles see Trigonometric Identities.

### Law of Sines

The **Law of Sines** (also known as The Sine Rule) is:

it can also be this way around:

### Law of Cosines

The **Law of Cosines** (also known as The Cosine Rule) is an extension of the Pythagorean Theorem to any triangle:

which can also be re-arranged to:

### Law of Tangents

The Law of Tangents is: