Combinations = n! / (n - r)! r!

In this case:
n = 4
r = 3
Combinations = 4! /(4-3)! 3! = 24/(1)(6) = 24/6 = 4
Answer:
4 arrangements
The length of the radius of circle o is 18 cm.
<h2>
</h2><h2>
Given that</h2>
Circle o has a circumference of 36π cm.
<h3>
We have to determine</h3>
What is the length of the radius, r?
<h3>According to the question</h3>
Circle o has a circumference of 36π cm.
The length of the radius of the circle is determined by the following formula;

Substitute all the values in the formula;

Hence, the length of the radius of circle o is 18 cm.
To know more about Circumference click the link given below.
brainly.com/question/4268218
Answer:
sure ill help
Step-by-step explanation: