Answer:
On a keyboard you would type sqrt(41)
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Work Shown:
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A slight alternative is to plot the point M(2,-5) to form right triangle LMN. The 90 degree angle is at point M.
The legs are of length LM = 4 and MN = 5, which are found by subtracting the x coordinates together and the y coordinates together (or you can count the spaces). From there, use the Pythagorean theorem to get the hypotenuse LN.
The distance formula is an altered version of the Pythagorean theorem.