The distance formula is Distance x 2 x 1 2 y 2 y 1 2. Use the distance formula to determine the distance between the two points. When we know the horizontal and vertical distances between two points we can calculate the straight line distance like this.
Lets pick B and C.
To carry on the example. The linear distance between the two points is the square root of the sum of the squared values of the x-axis distance and the y-axis distance. Use the distance formula to determine the distance between the two points. The width is the distance between B and C or AD.