Answer
The answer from task $82$ is $3\sqrt{10}$, which is the same as the sum of the values from $80$ and $81$.
Distance between the first and fourth points is the same as the sum of distances between first two points and between second and fourth points.
Work Step by Step
The answers from task $80$ and $81$ are $\sqrt{10}$ and $2\sqrt{10}$, respectively.
Their sum is:
$$\sqrt{10}+2\sqrt{10}=3\sqrt{10}$$
The answer from task $82$ is $3\sqrt{10}$, which is the same as the sum of the values from $80$ and $81$.
Distance between the first and fourth points is the same as the sum of distances between first two points and between second and fourth points.
