Answer:
exterior angle = 36°
Step-by-step explanation:
In any polygon
exterior angle + interior angle = 180°
let x be the exterior angle then interior angle is 4x , then
x + 4x = 180
5x = 180 ( divide both sides by 5 )
x = 36
thus exterior angle = 36°
The area of D is given by:

The average value of f over D is given by:
8.2 is 10% of 82
As 8.2 * 10 is 82.