Given that DE || BC, AD : DB = 3 : 4, find out ar(∆ADE)/ar(∆ABC)?

Ratio of the number of sides of two regular polygons is 5 : 6 and the ratio of their each interior angle is 24 : 25. Then the number of sides of these two polygons are 

(2x + 4) and (x - 1) are the angle pairs of angles of measurement, then their measurement will be

In the triangle ABC, AB = 2 cm, BC = 3 cm and AC = 4 cm. D is the middle point of AC. If a square is constructed on the side BC, what is the area of the square?

Each internal angle of regular polygon is two times its external angle. Then the number of sides of the polygon 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 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). 

Each interior angle of a regular polygon is 144⁰. The number of sides of the polygon is