A ladder makes 45° with the ground when it leans against a wall. The ladder slides down by 4 m along the wall and finally makes an angle of 30° with the ground. Find the length of the ladder.
A ladder makes 45° with the ground when it leans against a wall. The ladder slides down by 4 m along the wall and finally makes an angle of 30° with the ground. Find the length of the ladder. Correct Answer 4√2(2 + √2)
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According to given data,
AC = DE = ladder length
BE = AB – 4
In ΔABC,
Sin45° = AB/AC
AC = AB√2
Now in ΔBED,
Sin30° = BE/ED
DE = 2BE
Substitute, BE = AB – 4 and DE = AC = AB√2
AB√2 = 2(AB – 4)
⇒ AB = 4(2 + √2)
∴ AC = 4√2(2 + √2)
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Feb 20, 2025