Answer:
Step-by-step explanation:
The complete statement would be
A corollary to a theorem is a statement that follows immediately from the theorem.
A corollary is defined as a true proposition derived from a theorem, which is a true statement that was demonstrated.
In geometry there are plenty corollaries which can be seeing as deduction, which are true because they are deducted by theorems which are true.
For example, there is a theorem that states "two angles that form a straight angle are supplementary". And a corollary of that theorem is "where two lines intersect, opposite angles are equal"