Afurniture rental company charges a fixed amount plus a fee based on the number of days for which the furniture is rented. the graph below shows the amount paid for a different number of days to rent the furniture: a graph titled furniture rentals plots the number of days on the x axis and the amount in dollars on the y axis. a straight line joins the ordered pairs 0, 80 and 4, 240. what is the fixed amount charged? $20 $40 $60 $80

The fixed amount that is charged is:

                     $ 80

Step-by-step explanation:

We are given a straight line joins the ordered pairs (0,80) and (4,240).

We know that  the equation of a line passing through two points (a,b) and (c,d) is calculated by:

Here we have:

       (a,b)=(0,80) and (c,d)=(4,240)

Hence, the equation of line is:

Hence, the fixed charge is the initial charge i.e. when the number of days i.e. x value is zero.

Hence, when x=0 we have:

          y=80

       Hence, the fixed charge is:  80

we have three similar triangles, because each has a right angle and shares an angle.   let's write the angles in order: opposite to short leg, long leg, hypotenuse.

cab similar to bad similar to cbd

or as ratios,

ca: ab: cb = ba: ad: bd = cb: bd: cd

we also know

ac = ad + cd

(ad+cd): ab: cb = ba: ad: bd = cb: bd: cd

(ad+cd)/cb=cb/cd

we have cb=6, ad=5 and seek x=cd.

we reject the negative root and conclude x=4

answer: 4