Answer:

Step-by-step explanation:
A ratio is a comparison of two quantities and can be written in several forms including fractions. It is most commonly written in fraction form or a:b.
To write a ratio, we count the number of each quantity we are comparing or use the variable for that quantity. We write radius:circumference. Recall, the circumference of a circle can be found using
or
.
We write r:
or r:
.
We can also write in fraction form:
or 
Answer: 9, 1/20, 9/20
Step-by-step explanation:
1) 9 pieces
2) Size of each pieces:

3) Area of the shaded rectangle:

Answer:
Step-by-step explanation:
Answer:
⇒ 
Step-by-step explanation: