By using the Pythagorean theorem, we can work out the length of the hypotenuse of a right-angled triangle if we know the length of the other two sides. To find the distance between two points and , we first locate the points on the Cartesian plane.
Next, we can construct a right triangle by drawing a horizontal line through and a vertical line through .
From the Pythagorean Theorem we know that .
Now, we need to determine the lengths a and b.
Then square each side to get closer to the form .