Question 882905
Use the distance formula,
{{{D^2=(x[2]-x[1])^2+(y[2]-y[1])^2}}}
{{{D^2=(2-7)^2+(12-2)^2}}}
{{{D^2=25+100}}}
{{{D^2=125}}}
{{{D=sqrt(125)}}}
{{{D=5sqrt(5)}}}