Answer:
r = 1
Step-by-step explanation:
we know that :
[tex]Slope=\frac{y_{B}-y_{A}}{x_{B}-x_A}[/tex]
Then
[tex]\frac{5}{4} =\frac{16-r}{-3-(-15)}[/tex]
Then
[tex]\frac{5}{4} =\frac{16-r}{12}[/tex]
Then
5×12 = 4×(16-r)
Then
60 = 64 - 4r
Then
4r = 64 - 60
Then
4r = 4
Then
r = 1
