To find the angle formed by the ladder where it rests against the house, we can use the inverse sine function (arcsin).
We have:
- The length of the ladder (hypotenuse) = 20 feet
- The distance from the base of the ladder to the house (adjacent side) = 4 feet
We can find the height (opposite side) using the Pythagorean theorem first:
\[ \text{height}^2 + 4^2 = 20^2 \] \[ \text{height}^2 + 16 = 400 \] \[ \text{height}^2 = 384 \] \[ \text{height} = \sqrt{384} \approx 19.6 \text{ feet} \]
Now we can find the angle θ using the sine function:
\[ \sin(\theta) = \frac{\text{opposite}}{\text{hypotenuse}} = \frac{19.6}{20} \]
Now, we take the inverse sine:
\[ \theta = \arcsin\left(\frac{19.6}{20}\right) \approx \arcsin(0.98) \]
Calculating that gives us an angle approximately equal to:
\[ \theta \approx 78° \]
So, the approximate angle formed where the ladder rests on the house is 78°.