Step-by-step explanation:
1. Set up your diagram (see above).
The box indicates a 90 degree angle. We know it's 90 degrees because the house is perpendicular to the ground.
2. Determine what you know.
We are given the height of the ladder, and the angle it makes with the ground. I've labeled those on the diagram. The ladder acts as the hypotenuse of the right triangle that we have set up.
3. Set up your equation.
Since we have a right triangle, we can use right triangle trigonometric identities: SOH CAH TOA. This means that
sin = opposite / hypotenuse
cos = adjacent / hypotenuse
tangent = opposite/ adjacent
Since we were given the hypotenuse and want to find how far away the bottom of the ladder is, we will need to use cosine. Now we can set up our equation like so:
cos (68) = A / 12
4. Solve
cos (68) = A / 12
A = 12 * cos (68)
A = 4.495 feet
Answer:
4.495 ft
