## Explanation

The length of a line can be calculated with the distance formula, which looks like this:

Distance is the square root of the change in x squared plus the change in y squared, where two points are given in the form (x_{1}, y_{1}) and (x_{2}, y_{2}). The distance formula is an example of the Pythagorean Theorem applied, where the change in x and the change in y correspond to the two sides of a right triangle, and the hypotenuse is the distance being computed.

In Excel, the distance formula can be written with the exponent operator (^) and the SQRT function like this:

```
=SQRT((D5-B5)^2+(E5-C5)^2)
```

Following Excel's order of operations, the change in x and the change in y is calculated, then squared, and the two results are added together and delivered to the SQRT function, which returns the square root of the sum as a final result:

```
=SQRT((D5-B5)^2+(E5-C5)^2)
=SQRT((6)^2+(8)^2)
=SQRT(36+64)
=SQRT(100)
=10
```

The POWER function can also be used instead of the exponent operator (^) like this:

```
=SQRT(POWER(D5-B5,2)+POWER(E5-C5,2))
```

with the same result.