In mathematical reasoning, a statement that results immediately from a proposition that has already been demonstrated as a clear consequence.

A corollary is a simple proposition that results from the proposition demonstrated by reasoning.

### Example

Here is a proposition:

*The measure in degrees of an inscribed angle is equal to half of the measure in degrees of the arc intercepted on the circle by its sides. *

If m\(\stackrel{\frown}{\textrm{AB}}\) = 84,

then m\(∠{\textrm{ABC}}\) = 42.

A corollary resulting from this proposition would be:

*Every inscribed angle in a half-circle is a right angle.*

m\(∠{\textrm{ABC}}\) = 90.