Subtract the x-coordinate of the first point from the x-coordinate of the second point. For example, if your first two points on the shape are (5,4) and (14,16), subtract 5 from 14 to get 9.
Square the difference in x-coordinates. In this example, square 9 to get 81.
Subtract the y-coordinate of the first point from the y-coordinate of the second point. For example, if your first two points on the shape are (5,4) and (14,16), subtract 4 from 16 to get 12.
Square the difference in y-coordinates. In this example, square 12 to get 144.
Add the two squared distances and take the square root of the result to find the distance between the two points. In this example, add 81 to 144 to get 225 and take the square root of 225 to find the distance from point-to-point is 15.
Repeat the Steps 1 to 5 to find the distance between successive points that define the shape. For example, if you have a four-sided figure, you also need to calculate the distance between the second and third points, the third and fourths points and the fourth and first points.
Add the four distances to find the perimeter of the shape on the coordinate grid worksheet. For example, if the distances equal 15, 17, 12 and 14, the perimeter equals 58.