Answer:
[tex]\sqrt{85}[/tex]
Step-by-step explanation:
we have the equation of distance between two points :
d=[tex]\sqrt{(x2-x1)^2+(y2-y1)^2}[/tex]
first point (21,5)
second point (28,-1)
so we have
d=[tex]\sqrt{(28-21)^2+(-1-5)^2}[/tex]
d=[tex]\sqrt{(7)^2+(-6)^2}[/tex]
d=[tex]\sqrt{49+36}[/tex]
d=[tex]\sqrt{85}[/tex]
so we have
d=[tex]\sqrt{85}[/tex]