Triangle ABC is a right triangle where angle B = 90 degrees. The coordinates of A and B are (5,0) and (2,5) if the x-coordinate of point C is 7 what is the y coordinate?

Question

anonymous · Answer

@austinL can you help

anonymous · Answer

my choices are 7, 8, or 10
I was going with 7

mertsj · Answer

|dw:1392501492914:dw|

mertsj · Answer

What is the slope of BA?

anonymous · Answer

-5/3

mertsj · Answer

So the slope of the perpendicular must be ???

anonymous · Answer

5

mertsj · Answer

Change the slope to its reciprocal and change its sign.

anonymous · Answer

3/5 so it (7,8) am i doing this wrong

mertsj · Answer

Yes.  3/5 is correct.

mertsj · Answer

So from point B (2,5) go up 3 and right 5.  Where do you end up?

anonymous · Answer

so the coordinate of point C (7,8)

mertsj · Answer

(2, 5)  up 3 would mean that you add 3 to the y coordinate.
right 5 means add 5 to the x coordinate

mertsj · Answer

so yes.  (7,8) is the point.