We have to use the distance formula.
\(\sf~d=\sqrt{(x_2-x_1)^2+(y_2-y_1)^2}\)
(13, 20), (18, 8)
x1 y1 x2 y2
Plug in what we know:
\(\sf~d=\sqrt{(18-13)^2+(8-20)^2}\)
Subtract:
\(\sf~d=\sqrt{(5)^2+(-12)^2}\)
Simplify exponents:
\(\sf~d=\sqrt{25+144}\)
Add:
\(\sf~d=\sqrt{169}\)
Find the square root:
\(\sf~d=\boxed{\sf13}\)
