# law of cosines

### noun Trigonometry.

a law stating that the square of a side of a plane triangle is equal to the sum of the squares of the other two sides minus twice the product of the other sides multiplied by the cosine of the angle between them.

a law stating that the cosine of an arc of a spherical triangle equals the sum of the product of the cosines of the other two arcs added to the product of the sines of the other two arcs multiplied by the cosine of the angle between them.

## RELATED CONTENT

## Nearby words

- law of areas,
- law of averages,
- law of conservation,
- law of contiguity,
- law of contradiction,
- law of definite composition,
- law of diminishing marginal utility,
- law of diminishing returns,
- law of dominance,
- law of effect

Dictionary.com Unabridged
Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019