If each interior angle is doubled of each exterior angle of a regular polygon with n sides, then the value of n is 

PQR is a right angled triangle in which PQ = QR . If the hypotenuse of the triangle is 20 cm , then what is the area ( in cm ) of the triangle PQR ?

The measure of the angles of a triangle are in the ratio of 2 : 7: 11. Measure of angles are:

Equation of the straight line parallel to x-axis and also 3 units below x-axis is: 

In ΔPQR , ∠R=54° the perpendicular bisector of PQ at S meets QR at T. If ∠TPR =46°, then what value of (in degree) ∠PQR?

In triangle PQR, points A, B and C are taken on PQ, PR and QR respectively such that QC = AC and CR = CB. If ∠QPR = 40°, then ∠ACB is equal to: 

The lengths of one side of a rhombus and one of the two diagonals are 6 cm each. Find the area of the rhombus (in cm²). 

In triangle ABC a straight line parallel to BC intersects AB and AC at D and E respectively. If AB = 2AD then DE : BC is