# Curve

**Curve**is an object similar to a line but not be straight or we can say generalization of a line. We already know about a straight line. If we have a line segment, then we can find the length of the segment easily by simply measuring the length using a ruler or a scale or by placing the line segment on a grid. This is shown in the figure below

From the above figure we can easily state that the length of the given line segment is

**5 units**.__In another case if we have a line segment joining two points, we can find its length using the distance formula as follows:__

Here, we have the coordinates of the two points. So the distance between them can be found as follows:

$D$ = $\sqrt{((x_{2}\ -\ x_{1})^{2}\ +\ (y_{2}\ -\ y_{1})^{2})}$

$D$ = $\sqrt{((2\ -\ (-1))^{2}\ +\ (5-(-3))^{2})}$

$D$ = $\sqrt{(3^{2}\ +\ 8^{2})}$

**$D$ = $\sqrt{73}$**

Now we shall learn to do the same for a curve as well.