Answer:
20 side polygon: 180 x (20 -2)
Step-by-step explanation:
A n side polygon can be divided into n-2 triangles
each triangle has 180°
n-2 triangles have 180 x (n-2) degrees
The area of sector is 1.57 m²
<u>Explanation:</u>
Given:
Radius, r = 3 m
Central angle of a sector = 1/9π radians
Area of sector, A = ?
We know:
Area of sector, A = 
where,
α is the central angle in radians
On substituting the value we get:

Therefore, the area of sector is 1.57 m²
Frodo can run 1 miles in 1 hour
You can estimate 3.9 times 5.3 to 4 times 5 which is 20
so if the answer is around 20, you know that you will have exactly 2 digits before the decimal place