2 right angle = ?

Express the following angles in terms of a right angle . ((2pi)/3)^c

Find the locus of midpoint of chords of the circle x ^(2) + y ^(2) = r^(2) , substending a right angle at the point (a,b)

The triangle with vertices A (2, 7), B (4, y) and C(-2, 6) is right angled at A if

If the chord joining the points (2,-1),(1,-2) subtends a right angle at the centre of the circle,then its centre and radius are

Prove that the curves y^(2)=4axandxy=c^(2) cut at right angles if c^(4)=32a^(4)

Prove that the curves y^(2)=4ax and xy=c^(2) cut at right angles if c^(4)=32a^(4) .

Find the locus of a point,so that the join of (-5,1) and (3,2) subtends a right angle at the moving point.