Prove that angle in a semi circle is a rightangle by using Vector method.

Angle is a semi-circle is………

Prove that angle subtended by semicircle is 90^@ .

Angle in a semi -circle at the centre is …….

Let ‘O’ be the centre of a circle, PQ is a diameter, then prove that angle PRQ = 90^@ (OR) Prove that angle in a semi-circle is right angle.

Area of semi-circle is ……….

Central angle of circle is_______

Sum of the central angles in a circle is …………

Prove that in any triangle, the altitudes are concurrent by vector method.