Use the distance formula to find the perimeter of the triangle with vertices at the points (-1,0) (2,0) and (2,7). Round to two decimal places if necessary.

Answer 1

If you draw the figure on the coordinate axis you will see that you have a right triangle.

The side between (-1.0) and (2,0) is a straight line of length 3 and is a leg.

The side between (2,0) and (2,7) is a straight line of length 7 and is a leg,

The remaining side between (-1,0) and (2,7) is the hypotenuse, which can be found using the Pythagorean Theorem.

Hypotenuse = sqrt(3^2 + 7^2) = sqrt(58).

Answer 2

Note that for the distance formula, the order of subtraction

does not matter because the differences are squared

(-1,0) vs ( 2,0)

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sqrt ( (-1-2)^2 + (0-0)^2) = sqrt( (-3)^2 + 0^2) = sqrt( 9+0) = sqrt(9) = 3

(-1,0) vs ( 2,7)

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sqrt( (-1-2)^2 + (7-0)^2) = sqrt( (-3)^2 + (7)^2) = sqrt( 9+49) =sqrt(58)

(2,0) vs (2,7) has distance of 7

Answer is 10 + sqrt(58)

which is approximately 17.6157731058639082856614110271583