Q7 of 57 Page 73

A flag pole 18 m high casts a shadow 9.6 m long. Find the distance of the top of the pole from the far end of the shadow.

Let MN = 18 m be the flag pole and its shadow be LM = 9.6 m.

The distance of the top of the pole, N from the far end, L of the shadow is LN.



In right angled ∆LMN,


LN2 = LM2 + MN2 [by Pythagoras theorem]


⇒ LN2 = (9.6)2 + (18)2


⇒ LN2 = 9.216 + 324


⇒ LN2 = 416.16


∴ LN = √416.16 = 20.4 m


Hence, the required distance is 20.4 m


More from this chapter

All 57 →
5

A 5 m long ladder is placed leaning towards a vertical wall such that it reaches the wall at a point 4 m high. If the foot of the ladder is moved 1.6 m towards the wall, then find the distance by which the top of the ladder would slide upwards on the wall.

 6

For going to a city B from city A there is a route via city C such that AC⊥CB, AC = 2x km and CB = 2(x + 7) km. It is proposed to construct a 26 km highway which directly connects the two cities A and B. find how much distance will be saved in reaching city B from city A after the construction of the highway.

 7

A street light bulb is fixed on a pole 6 m. above the level of the street. If a woman of height 1.5 m casts a shadow of 3 m, then find how far she is away from the base of the pole.

 9

In given figure, ABC is triangle right angled at B and BD ⊥ AC. If AD = 4 cm and CD = 5 cm, then find BD and AB.