129 meter from the foot of a cliff on level of ground, the angle of elevation of the top of cliff is 30 °. The height of this cliff is 

The angle of elevation of an aeroplane from a point on the ground is 60°. After flying for 15 second, the angle of elevation changes to 30°. If the Aeroplane is flying at a height of 4500 meter, then what is the speed (in m/s) of aeroplane?

An electrician has to repair an electric fault on a pole of height 4 m. He needs to reach a point 1.3 m below the top of the pole to un dertake the repair work the length of ladder that he should use, which when inclined at an angle of 60° to the horizontal would enable him to reach the required positions is :

From the top of a lamp post of height x metres, two objects on the ground on the same side of it (and in line with the foot of the lamp post) are observed at angles of depression of 30° and 60°, respectively. The distance between the object is $$ {32{\sqrt{3}{\ meter}}}$$. The value of  x is:

From a point 12 meter above the water level, the angle of elevation of the top of a hill is 60° and the angle of depression of the base of the hill 30°. What is the height ( in meter) of the hill?

An observer who is 1.62-meter-tall is 45 meters away form a pole. The angle of elevation of the top of the pole from his eyes is 30°. The height ( in meter) of the pole is closet to:

The angle of elevation of the top of a building at a distance of 70 m from its foot on a horizontal plane is found to be 60°. Find the height of the building.

Two ship are on the opposite of a light house such that all three of them are collinear. The angels of depression of the two ships from the top of the light house are 30⁰ and 60⁰. If the ships are $$230 \sqrt { 3} \ $$ m apart, then find the height of the light house (in m).