Step-by-step explanation:
First of all we need to know the formula for the circumference which is:
We don't have the radius. What we only have is the area; therefore, we must use the area formula and extract the radius from it.
The formula for the area is: Solve for r;
Now that we've found the radius, we simply plug it into the circumference formula.
There are 400 balcony seats in the concert hall.
<u>Step-by-step explanation</u>:
Step 1 :
Total seats = Lower seats + balcony seats
Step 2 :
Tickets sold = 1/5 of total tickets.
⇒ 170 = (1/5)x
⇒ x = 5170
⇒ x = 850 tickets
∴ Total seats in the concert hall is 850.
Step 3 :
Total seats = 450 + balcony seats
850 - 450 = balcony seats
∴ balcony seats = 400