Quadratic relations help needed! Thank you

For this case we have that the distance between two points is:
[tex]d = \sqrt {(x_ {2} -x_ {1}) ^ 2 (y_ {2} -y_ {1}) ^ 2}[/tex]
We have the following points:
[tex](x_ {1}, y_ {1}) :( 3 \sqrt {7}, 2 \sqrt {5})\\(x_ {2}, y_ {2}) :( 5 \sqrt {7}, 5 \sqrt {5})[/tex]
Substituting:
[tex]d = \sqrt {(5 \sqrt {7} -3 \sqrt {7}) ^ 2+ (5 \sqrt {5} -2 \sqrt {5}) ^ 2}\\d = \sqrt {(2 \sqrt {7}) ^ 2+ (3 \sqrt {5}) ^ 2}\\d = \sqrt {4 (7) + 9 * (5)}\\d = \sqrt {28 + 45}\\d = \sqrt {73}\\d = 8.5440[/tex]
Answer:
[tex]d = 8.54[/tex]