Go Long Telephone Company charges a flat rate of $18.75 per month plus $0.18 per minute. To Call Telephone Company charges a flat rate of$12.51 per month plus $0.42 per minute. How many minutes would a customer need to use in order for the bill from Go Long and Via Call to be equal at the end of the month?

9514 1404 393

  26 minutes

Step-by-step explanation:

Let x represent the number of minutes used. The charges will be equal when ...

  18.75 +0.18x = 12.51 +0.42x

  6.24 = 0.24x . . . . . . . . . . . . . . . subtract 0.18x+12.51

  26 = x . . . . . . . . . . . . . . . divide by 0.24

A customer using 26 minutes will receive the same bill from either company.

x = central angle apc = measure of minor arc ac

the two angles x and 30 add to 180, so x+30 = 180 and x = 180-30 = 150. the measure of minor arc ac is 150 degrees.

what we need to do from here is find the circumference and then multiply it by x/360 since there are 360 degrees in a circle. in this case, x = 150, so x/360 = 150/360 = 15/36 = 5/12. the shortest distance along the curve from a to c is 5/12 of the distance around the entire circle (aka circumference)

c = circumference

c = pi*d

c = pi*24

c = 24pi

now multiply this by 5/12 to get

distance along minor arc ac = (5/12)*(circumference)

distance along minor arc ac = (5/12)*(24pi)

distance along minor arc ac = 10pi

the formula you can use is

l = (x/360)*pi*d

with

l = length of minor arc

x = central angle

d = diameter

which essentially is the steps we took though a bit differently.

the answer is 13 cm