Q4 of 168 Page 4

A ladder 17 m long reaches a window of a building 15 m above the ground. Find the distance of the foot of the ladder from the building.

In ⊿ ABC


AC2=AB2+BC2


172=152+BC2


289=225+BC2


BC2=289 – 225


BC2=64


BC=


BC=8 m


Distance of the foot of ladder is 8 m from the building.


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2

The sides of certain triangles are given below. Determine which of them are right triangles.

(i) a = 7 cm, b = 24 cm and c = 25 cm


(ii) a = 9 cm, b = 16 cm and c = 18 cm


(iii) a = 1.6 cm, b = 3.8 cm and c = 4 cm


(iv) a = 8 cm, b = 10 cm and c = 6 cm

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