Q6 of 19 Page 54

A 15 m long ladder reached a window 12m high from the ground. On placing it against a wall at a distance x m. Find x.


Let BC be the length of ladder i.e. 15 cm and the height of the window from the ground be AB i.e. 12 cm.


We know that in a right angled triangle, the square of the hypotenuse is equal to the sum of the squares of the other two sides.


⇒ In ΔABC, BC2 = AB2 + AC2


⇒ 152 = 122 + x2


⇒ 225 = 144 + x2


⇒ x2 = 225 – 144 = 81


∴ x = √81 = 9 cm


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