# Midpoint Formula

The midpoint formula is used to find a point (its coordinate values) that is located exactly between two other points in a plane. The formula finds its tremendous application in geometry.

The coordinates of the point (x, y) that lies exactly halfway between the two points (x1, y1) and (x2, y2) are given by:

 x = ( x_(1 )+ x_2)/2 , y = ( y_(1 )+ y_2)/2

Similarly, if we want to find the midpoint of a segment in the 3-dimensional space, we can determine the midpoint using:

 x = ( x_(1 )+ x_2)/2 , y = ( y_(1 )+ y_2)/2 , z = ( z_(1 )+ z_2)/2

The figure shown below gives an illustration of the midpoint formula.

##### Explanation:

While calculating the midpoint between two sets of coordinates of a line segment, if we assume, point A is x1, y1 and x2, y2. Using the above midpoint formula, the average of the x coordinates and y coordinates give the midpoint of Point A and Point B. It is possible to find the midpoint of a vertical, horizontal and even a diagonal line segment using this formula.

## Find the coordinates of the midpoint between (-1, 4) and (3, 6).

#### Explanation:

Using the coordinate values as x_1 = -1, y_1 = 4, x_2 = 3, y_2 = 6

The coordinates of the Midpoint can be found using the midpoint formula:

 x = ( x_(1 )+ x_2)/2 , y = ( y_(1 )+ y_2)/2

 => x = ( -1+ 3 )/2 , y = ( 4 + 6 )/2

 => x = 1 , y = 5

Therefore, the midpoint is (1,5).

We can prove that the point (1,5) lies halfway between the two given points using distance formula discussed in the previous section.

## Find point B, if midpoint of Point A(7, -10) and point B(x',y') is (4, -6).

#### Explanation:

Let us assume that the coordinates of point B are (x', y'). Now by making use of the midpoint formula:

 x = ( x_(1 )+ x_2)/2 , y = ( y_(1 )+ y_2)/2

Here we have x_1 = 7, y_1 = -10, x_2 = x', y_2 = y', x = 4, y = -6

 => 4 = ( 7 + x^')/2 , -6 = (-10 + y^')/2

Multiplying on both sides by 2 gives

 => 8 = 7 + x' , -12 = -10 + y'

 => x' = 1 , y' = -2

Therefore, the midpoint is (1,-2).

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