Question 185287
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Not quite sure about the endpoint being referred. But see below,
Let's put the given in graph:
{{{drawing(400,400,-5,10,-5,18,grid(1),graph(400,400,-5,10,-5,18),circle(7,0,.16),circle(0,15,.16),green(line(7,0,0,15)))}}}--->shown endpoints (7,0) & (0,15)
In this case, to find the "DISTANCE" (green line), we do it thru Distance Formula (variant with Pythagorean Theorem).
{{{drawing(300,300,-1,8,-1,16,line(0,0,7,0),line(0,0,0,15),green(line(7,0,0,15)),locate(-.2,0,0),locate(7.2,0,7),locate(0,15.5,15),line(0,.8,0.4,.8),line(.4,.8,.4,0))}}}
Continuing,
{{{d^2=(y[2]-y[1])^2+(x[2]-x[1])^2}}}
{{{d^2=(15-0)^2+(7-0)^2=225+49=274}}}
{{{highlight(d=sqrt(274))}}}, Answer 
Thank you,
Jojo</pre>