Answer:
The answer is β=0,85 rads
Explanation:
As the ladder is leaning against the building, we can imagine there´s a triangle where 20ft is the hypotenuse and 15ft is the maximum vertical distance between the ladder and the ground, it means, the leg opposite to β which is the angle we need
Let β(betha) be the angle between the ladder and the ground
We also know that
In this case we will need to find β, this way:
Then β=48,6°
We also have that 2πrads is equal to 360°, in this way we find how much β is in radians:
then we find β=0,85rads