Question

how long a ladder must you have to reach the top of a 15-foot wall if the bottom of the ladder is placed 4 feet from the base of the wall? round to the nearest tenth of a foot.

14.5 ft
15.5 ft
17.0 ft
19.0 ft

Explanation:

Set up the Pythagorean equation

$$ a^2 + b^2 = c^2 $$

$$ 15^2 + 4^2 = c^2 $$

Solve for the hypotenuse

$$ 225 + 16 = c^2 $$

$$ 241 = c^2 $$

$$ c = \sqrt{241} \approx 15.524 $$

Round to the nearest tenth

$$ c \approx 15.5\text{ ft} $$

Answer:

• (A) 14.5 ft
• (B) 15.5 ft (Correct answer)
• (C) 17.0 ft
• (D) 19.0 ft