Answer:
The scale factor is 3.
Step-by-step explanation:
Let the scale factor be x
The center of the dilation is origin (0,0) and the point E (5,3) becomes E'(15,9)
Dilation involves multiplication. Hence, when we multiply 3 with 5 then we will get 15 and also when 3 multiplied by 3 the result is 9.
This, when we multiply the coordinates of E by 3, we get the coordinates of E'.
Therefore, the scale factor is 3.
