If diagonals of a rhombus are 16 cm and 30 cm. then what is the perimeter (in cm) of the rhombus?

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?

Given that (a²+b²)=60, then find the value of (a+b)²+(a–b)².

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

ABCD is cyclic quadrilateral Sides AB and DC, when produced, meet at E, and sides BC and AD, When produced, meet at F. If ∠BFA=60° and ∠AED=30°, then the measure of ∠ABC is:

In the figure below, find the value of AB.

AD is the median of a triangle ABC and O is the centroid such that AO = 10 cm. The length of OD (in cm) is 

The length of the common chord of two circles of radii 30 cm and 40 cm whose centers are 50 cm apart is (in cm)