Answer:
Theorems
Explanation:
Theorems is the right answer.
A circle is a geometric figure where all points on the circle keep equal distances from a point called the centre.
A circle has so many important properties.
The important of these are called theorems related to circles.
Some of the theorems are
i)Central angle theorem
ii) Opposite angles are supplementary for a cyclic quadrilateral, etc
Hence theorems would be the appropriate word for filling up the answer