Home › UP Board Class 10 › mathematics › Some Applications of Trigonometry › If the angle of depression of an object from the…
If the angle of depression of an object from the top of a tower is 30 degrees, the angle of elevation of the tower top from the object is
A45 degrees
B30 degrees
C60 degrees
D90 degrees
Answer & Solution
Correct answer: B. 30 degrees
1. Angle of depression and angle of elevation are alternate interior angles.
2. They are always equal when lines of sight cross parallel horizontals.
3. Hence the elevation equals 30 degrees.
_Source: NCERT Class 10 Mathematics, Ch 9 "Some Applications of Trigonometry", §9.2_
Related questions
From the top of a 7 m building, the angles of elevation of the top and angle of depressionThe shadow of a 30 m tall tower becomes 30/(square root of 3) m shorter when the sun risesFrom the top of a 10 m tower, the angle of depression of an object on the ground is 60 degA man standing on the deck of a ship 8 m above water level observes the angle of elevationThe angle of elevation of the top of a building from the bottom and top of a tower are 60 The angles of elevation of the top of a tower from two points A and B at distances of 4 m A tree breaks due to a storm and the broken part bends so that its top touches the ground An aeroplane at an altitude of 1500 m makes an angle of depression of 60 degrees with a fi