Difficulty: Easy
Correct Answer: 9.2 m
Explanation:
Introduction / Context:
A ladder against a wall forms a right triangle with the ground (adjacent) and wall (opposite). The angle with ground and the horizontal distance to the wall are known; find the hypotenuse (ladder length).
Given Data / Assumptions:
Concept / Approach:
Use cos θ = adjacent / hypotenuse → hypotenuse = adjacent / cos θ.
Step-by-Step Solution:
Verification / Alternative check:
Compute vertical reach: L * sin 60° = 9.2 * (√3/2) ≈ 7.97 m; Pythagoras with 4.6 m confirms hypotenuse ≈ 9.2 m.
Why Other Options Are Wrong:
2.3 and 4.6 m are too short; 7.8 m corresponds to cos near 0.59, not 0.5.
Common Pitfalls:
Using tan instead of cos; mixing degrees with radians; rounding too early on √3 or cos values.
Final Answer:
9.2 m
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