The angle of elevation of the top of an unfinished building at point P which is 120 m away from its base is 30°. If the angle of elevation of the finished building at the same point would be 60°, find the height of the remaining part of the building.
| Question | The angle of elevation of the top of an unfinished building at point P which is 120 m away from its base is 30°. If the angle of elevation of the finished building at the same point would be 60°, find the height of the remaining part of the building. | |
| Type | multiple_choice | |
| Option | 70 √3 m | incorrect |
| Option | 75 √3 m | incorrect |
| Option | 80 √3 m | correct |
| Option | 85 √3 m | incorrect |
Let the height of remaining part of building be X.
then,
120 + √3 X = 120*3
120 + √3 X = 360
√3 X = 360 – 120
√3 X = 240
