$\"\"$

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A plane passes over a ground radar station at an altitude of $\"\"$ km.

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Speed of the plane is $\"\"$ km/h.

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The plane is climbing at an angle of $\"\"$ radians.

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$\"\"$

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Assume the radar is located at point $\"\"$ .

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The plane is located at an altitude of $\"\"$ km is located at point $\"\"$ .

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After $\"\"$ min, the plane climbs at an angle of $\"\"$ is located at point $\"\"$ .

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Observe the figure,

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$\"\"$ km.

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Assume $\"\"$ and $\"\"$ .

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Speed of the plane is $\"\"$ km/h.

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Total angle at $\"\"$ is $\"\"$ .

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Apply cosine rule to the above triangle.

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$\"\"$ .

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Substitute corresponding values in above expression.

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$\"\"$

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Find distance traveled by the plane in one minute.

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Distance $\"\"$ .

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$\"\"$ .

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Substitute $\"\"$ in $\"\"$ .

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$\"\"$

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$\"\"$

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Consider $\"\"$ .

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Disorientate on each side with respect to $\"\"$ .

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$\"\"$

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Substitute $\"\"$ , $\"\"$ and $\"\"$ .

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$\"\"$

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Distance from the plane to the radar station is increasing at $\"\"$ km/h.

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$\"\"$

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Distance from the plane to the radar station is increasing at $\"\"$ km/h.