If you rounded it it would be 4.6
In Graph x-axis represents number of visits and y-axis represents cost.
As graph comes up to be a linear one, so we can clearly say that cost is increasing linearly in multiples of 5.5 with increase in number of visits.
Example :
If museum is visited once then cost (y) = 5.5 x 1 = 5.5
If museum is visited twice then cost (y) = 5.5 x 2 = 11
If museum is visited thrice then cost (y) = 5.5 x 3 = 16.5
... cost (y) goes on in creasing when number of visits (x) increase with multiples of 5.5
Let us find the co ordinates of each vertex of the triangle .
Vertex A ( in firs second quadrant) = ( -5 ,3)
vertex B in third quadrant = ( -5, -5)
vertex C in fourth quadrant = ( 4, -2)
let us use distance formula AB^2 = ( -5 - 3)^2 + (-5 - -5 )^2 = 64 + 0
AB= 8
BC^2 = ( -2 - -5 )^2 + ( 4 - - 5)^2 = 9 + 81 = 90
BC = 9.48
AC^2 = ( -2 -3)^2 +( 4- -5)^2 = 25 + 81 = 106
AC= 10.29
Perimeter = sum of length of AB+ BC+ Ac = 8 + 10.29 + 9.48= 22.77