If sin x = 12/13, where 0° < x < 90°, find the value of 1 - cos\(^2\)x

The angle of elevation of the top of a tower from a point on the horizontal ground, 40m away from the foot of the tower is 30o. Find the height of the tower.

At a point 500m from the base of a water tank the angle of elevation of the top of the tank is 45o. Find the height of the tank,

Find the median of the following set of numbers: 28, 29, 39, 38, 33, 37, 26, 20, 15, 25