Answer:
3
Step-by-step explanation:
We can use the formula of slope to find this answer.
The formula to find the slope is y2-y1/x2-x1.
The slope of line ST is 1/5: 2-0/5-(-5); 2/10=1/5
We know that for two lines to be perpendicular, they have to have reciprocal opposite slopes. For example, if the slope of a line is 2/1 then the slope of a line perpendicular is -1/2.
Therefore, the perpendicular line should have a slope of: 1/5------>-5
To find which answer it is, follow the steps below:
y2-y1/x2-x1
plugin known values
-2-y1/0-(-1)
-2-y1/1
In order to make this -5, y1 needs to be 3
-2-3/1=-5
3 is the correct value