Question

Explain the distance formula. Then use it to calculate the distance between A(1,1) and B(7,-7).

Answer 1

The distance formula:
$d= \sqrt{ (x_{2} - x_{1}) ^{2}+ (y_{2} -y_{1}) ^{2} }$


A(1,1)    B(7,-7)

$d= \sqrt{ (7 - 1) ^{2}+ (-7 -1) ^{2} }$

$d= \sqrt{ (6) ^{2}+ (-8) ^{2} }$

$d= \sqrt{ 36 + 64 }$

$d= \sqrt{ 100 }$

$d=10$


The answer is 10