At the foot of a mountain, the elevation of its summit is 45o, after ascending 1000 m towards the mountain up a slope of 30o inclination, the elevation is found to be 60o. Find the height of the mountain.


Let AB be the mountain, so the at the foot of a mountain the elevation of its summit is 45o


So, ACB = 45°


Now when moving on the slope of 30° by a distance of 1000m,


i.e., the CD is the distance moved on the slope of 30° towards the mountain,


Hence CD = 1000m………..(i)


And DCF = 30°


Let EB = FD = x……..(ii)


DE = FB = z…….(iii)


CF = y and AE = t………(iv)


So after moving 1000m, the elevation becomes 60°,


So ADE = 60°


In ΔDFC,





And





Hence


In ΔADE,




t = z√3………(vi)


In ΔABC,





t + x = y + z


z√3 + 500 = 500√3 + z (from (iv), (v), (vi))


z√3-z = 500√3-500


z(√3-1) = 500(√3-1)


z = 500m……(vii)


Hence the equation (vi) becomes,


t = z√3 = (500) √3 m


Hence the height of the mountain is


AB = AE + EB = t + x = (500√3 + 500)m


So the height of the mountain is 500(√3 + 1)m.


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