2sin[(C+D)/2].sin[(D­-C)/2] is equal to

What is the value of sec 5π/4?

If the volume of a cylinder is 385 cubic cm and height is 10 cm, find its radius?

In a triangle, the length of the side opposite the angle which measures 45° is 16 cm, what is the length of the side opposite to the angle which measures 90°? 

In ΔABC, the angle bisector of ∠A cuts BC at E. Find the length of AC if lengths of AB, BE and EC are 9.6 cm, 4 cm and 3 cm?

A thief is stopped by a policeman from a distance of 200 metres. When the policeman starts the chase, the thief also starts running. Assuming the speed
of the thief as 8 km/hr and that of police man as 10 km/hr. How far the thief would have run, before he is over ­taken?

What is the equation of the line which passes through the points (3,­2) and (5,3)?

The distance between the points (11,­5) and (k,0) is 13. Find k.