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CAT 1995 — QA Question 28

Basics of TrianglesEasy

The length of a ladder is exactly equal to the height of the wall it is learning against. If lower end of the ladder is kept on a stool of height 3 m and the stool is kept 9 m away from the wall, the upper end of the ladder coincides with the top of the wall. Then the height of the wall is

Answer & solution

Correct answer: 15 m

  • A

    12 m

  • 15 m

  • C

    18 m

  • D

    11 m

Solution

The figure can be drawn as shown above.

Height of the wall = AD = AC = (AB + 3) or AB = (AC – 3).

In right-angled triangle ABC, AB2 + BC2 = AC2.

Thus, (AC – 3)2 + 81 = AC2.

∴ AC = 15 m.

Hence, height of the wall = 15 m.

Hence, option (b).

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CAT 1995 QA Q28: The length of a ladder is exactly equal to the height of the wall it is learning against. If lower end of the — Solution | TheCATExam