A20-foot support post leans against a wall, making a 70° angle with the ground. to the nearest tenth of a foot, how far up the wall will the support post reach?

To solve this problem you must apply the proccedure shown below:
 1. You have that the 20-foot support post makes a 70° angle with the ground. Therefore, you have:
 Sinα=opposite/hypotenuse
 α=70°
 opposite=x
 hypotenuse=20
 2. When you substitute the values, you obtain:
 Sin(70°)=x/20
 3. Now, solve for x:
 x=20Sin(70°)
 x=18.8
 The answer is: 18.8 feet