Two pillars of equal lengths stand on either side of a road which is 100 m wide, exactly opposite to each other. At a point on the road between the pillars, the angles of elevation of the tops of the pillars are 60° and 30°. Find the length of each pillar and distance of the point on the road from the pillars. (Use 3=1.732)
Solution
1
Let AB and CD be two pillars of equal length h m and let P be the point on road x m away from pillar CD.
+1 mark
2
In △CDP: tan60°=3=xh⇒h=3x ... (i)
+1 mark
3
In △ABP: tan30°=31=100−xh⇒h=3100−x ... (ii)
+1 mark
4
Solving (i) and (ii): 3x=3100−x⇒3x=100−x⇒x=25
+1 mark
5
h=253=25×1.732=43.3 m. Distance from pillars is 75 m and 25 m respectively.
+1 mark
Practice this question interactively with step-by-step AI feedback