Question

Points R(2,-1) and S(-5,3) are in the standard (x,y) coordinate plane. What is the length of RS in coordinate units?

A. 10

B. 65

C. 2√13

D. √33

E. √65

Answer 1

`\bf ~~~~~~~~~~~~\textit{distance between 2 points} \\\\ R(\stackrel{x_1}{2}~,~\stackrel{y_1}{-1})\qquad S(\stackrel{x_2}{-5}~,~\stackrel{y_2}{3})\qquad \qquad d = √(( x_2- x_1)^2 + ( y_2- y_1)^2) \\\\\\ RS=√([-5-2]^2+[3-(-1)]^2)\implies RS=√((-5-2)^2+(3+1)^2) \\\\\\ RS=√(49+16)\implies RS=√(65)`