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Question
A kite is flying at a height of 30 m from the ground. The length of string from the kite to the ground is 60 m. Assuming that there is no slack in the string, the angle of elevation of the kite at the ground is
Options
A. 45°
B. 30°
C. 60°
D. 90°
Solution
Let A be the position of the kite and AC be the length of the string of the kite.
Suppose θ be the angle of elevation of the kite at the ground.
It is given that, AB = 30 m and AC = 60 m.
In right ΔABC:
`sinO/= (AB)/(AC)` `[therefore=(\text{Perpendicular})/(text{Hypotenuse})]`
`thereforesinO/=30/60`
`rArrsinO/=1/2`
`rArr sinO/=sin30^@`
`rArrsinO/=sin30^@`
`rArr=O/=30^@`
Thus, the angle of elevation of the kite at the ground is 30°.
Hence, the correct answer is B
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