Sylvia is replacing a piece of siding on her house. To make the 12 ft. ladder stable, the bottom of the ladder needs to be 6 ft. from the base of her house. Applying the Pythagorean Theorem and rounding to the nearest tenth, how high will the ladder reach so that Sylvia can replace the siding?(1

1 answer

To determine how high the ladder will reach against the house, we can use the Pythagorean Theorem, which states:

\[ a^2 + b^2 = c^2 \]

where:

  • \( a \) is the height the ladder reaches on the wall,
  • \( b \) is the distance from the base of the ladder to the wall,
  • \( c \) is the length of the ladder.

In this case, we have:

  • \( c = 12 \) ft (the length of the ladder),
  • \( b = 6 \) ft (the distance from the base of the ladder to the wall).

We need to find \( a \):

  1. Substitute the known values into the Pythagorean theorem: \[ a^2 + 6^2 = 12^2 \]

  2. Calculate \( 6^2 \) and \( 12^2 \): \[ a^2 + 36 = 144 \]

  3. To find \( a^2 \), subtract 36 from both sides: \[ a^2 = 144 - 36 \] \[ a^2 = 108 \]

  4. Now, take the square root of both sides to find \( a \): \[ a = \sqrt{108} \]

  5. To simplify \( \sqrt{108} \): \[ \sqrt{108} = \sqrt{36 \times 3} = \sqrt{36} \times \sqrt{3} = 6\sqrt{3} \]

  6. Now calculate \( 6\sqrt{3} \) approximately: \[ \sqrt{3} \approx 1.732 \] \[ 6\sqrt{3} \approx 6 \times 1.732 \approx 10.392 \]

Rounding to the nearest tenth, the height the ladder will reach is approximately:

\[ \text{Height} \approx 10.4 \text{ ft} \]

Therefore, the ladder will reach about 10.4 ft high on the house.