Fill in the blanks:
The centre of a circle touching the three sides of a triangle internally is the point of concurrence of ………… of the triangle.

Fill in the Blanks: Chords _____ from the centre of a circle are equal in length.

The vertices of a triangle are (4, -3), (-2, 1) and (2, 3). Find the co-ordinates of the circumcentre of the triangle. [Circumcentre is the point of concurrence of the right-bisectors of the sides of a triangle.]

Fill in the Blanks: Equal arcs of a circle subtend_____ angles at the centre.

Fill in the blanks : A tangent to a circle intersects it in ............... point(s).

Fill in blanks- A secant drawn to a circle intersect the circle in ____points.

D,E and F are the middle points of the sides of the triangle ABC, then

Sum of the three sides of a triangle is less than the sum of its three altitudes.

The lengths of three sides of a triangle are 20 cm, 16 cm and 12 cm. The area of the triangle is