If the measure of an angle is D and R respectively in degree and radian, prove that `D/9=(20R)/pi`

D and E are points on the sides CA and CB respectively of a triangle ABC right angled at C.Prove that, AE^2+BD^2=AB^2+DE^2 .

If the sums of an A.P. upto pth, qth and rth terms are a, b and c respectively, prove that- a/p(q-r)+b/q(r-p)+c/r(p-q)=0 .

The measures of the angles of a triangle are in A.P. If the greatest angle is double the least angle, express the angles of the triangle in degree and radian.

Find the measure of each exterior angle of a regular polygon of 9 sides

The bisector of angleC and angleG of two similar triangle ABC and EFG are meet the side AB and EF respectively at the point D and H.Prove that triangleDCA~triangleHGE

The pth, qth and rth term of a G.P. are x, y, z respectively, then prove that- x^(q-r).y^(r-p).z^(p-q)=1 .

Area of a sector of angle p^@ of a circle with radius R is

O is a point within the ∆ABC . P, Q , R are three points on OA , OB and OC respectively such that PQ||AB and QR||BC . Prove that RP||CA .

The angles of a triangle are in A.P. and the ratio of number of degree in the least angle to the number of radian in the greatest angle is 60 :pi . Find the angles in degree.

Express the following statements by equations : The sum of the degree measures of the three angles of a triangle is 180^@ . The measure of the 2nd angle is twice that of the 1st and exceeds the thrid angle by 40^@ .