Question
The angle of elevation of the top of a building from a
point on the ground is 60°. After walking 20 meters towards the building, the angle of elevation becomes 75°. Find the initial distance from the point on the ground to the building.Solution
Let the height of the building be h meters, and the initial distance from the point on the ground to the building be d. From the first observation: tan(60°) = h/d, so h = d√3. From the second observation: tan(75°) = h/(d - 20). 2+√3= d√3/(d - 20)  d = 10(√3+2) meters. Correct option: c
3Â Â Â Â Â Â Â Â Â 6Â Â Â Â Â Â Â Â Â 18Â Â Â Â Â 149Â Â Â Â Â Â Â Â 602Â Â Â Â Â Â Â Â 15057
...1, 1, 3, 15, 105, 942
- Find the wrong number in the given number series.
8, 14, 24, 49, 59, 84 2, 4, 16, 48, 240, 1440, 10080
1001, 934, 863, 790, 711, 630, 539
Find the wrong number in the given number series.
1728, 121, 1000, 729, 512, 49
Find the wrong number in the given number series.
21, 31, 11, 41, 1, 61Find the wrong number in the given number series.
548, 532, 568, 510, 604, 460
9Â Â Â Â Â Â Â Â Â Â Â Â Â 17Â Â Â Â Â Â Â Â Â Â 53Â Â Â Â Â Â Â Â Â Â 103Â Â Â Â Â Â Â Â 310Â Â Â Â Â Â Â Â 619
...43, 42, 41, 39, 33, 10
