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
The molarity remains the same so the ratio does not change
Our bodies emit heat, and nerve endings in our skin can detect it.
Our eyes can detect visible light, but our bodies don't emit that.
Answer:

Explanation:
We are given that
Diameter=d=
Thickness=
Radius=
Using 
Dielectric constant=8
Resistance =
Internal specific resistance=r=100 ohm cm=
Using 1 m=100 cm
Internal resistance per unit length=
Using 
Internal resistance per unit length=