Answer: 90
Step-by-step explanation:
c = 2πr
r = 15
d = 30
30π = 90
Answer:
9.) 
10.) 
11.)
minutes of calling would make the two plans equal.
12.) Company B.
Step-by-step explanation:
Let <em>t</em> equal the total cost, and <em>m,</em> minutes.
Set up your models for questions 9 & 10 like this:
<em>total cost = (cost per minute)# of minutes + monthly fee</em>
Substitute your values for #9:

Substitute your values for #10:

__
To find how many minutes of calling would result in an equal total cost, we have to set the two models we just got equal to each other.

Let's subtract
from both sides of the equation:

Subtract
from both sides of the equation:

Divide by the coefficient of
, in this case: 

__
Let's substitute
minutes into both of our original models from questions 9 & 10 to see which one the person should choose (the cheaper one).
Company A:

Multiply.

Add.

Company B:

Multiply.

Add.

<em />
Answer: $15
Step-by-step explanation:
The normal price of the mirror is unknown we do not know that yet. So, let y represent the unknown number. The discount is 20 percent, we turn 20 into a decimal which would be 0.2. The amount of discount is $3. So, 0.2y equals to $3.
Then we divided.
y = 3 ÷ 0.2
And when you divide that is would be 15.
So, the regular price of the mirror is $15.
-2(y-3)=22
-2y+6=22
-2y=16
y=-8
Answer:

Step-by-step explanation:
We can see it on the given table of values.