# The equation of line XY is (y − 3) = (x − 4). What is the slope of a line perpendicular to XY?

Perpendicular lines are those lines that intersect at 90 degrees. Let's see how we can find the slope of a line perpendicular to another line.

## Answer: The slope of the line perpendicular to XY is -1.

Let's understand the problem in detail.

**Explanation:**

To find the slope of a line perpendicular to another line we will use the formula below

m_{1}m_{2 }= -1, where m_{1} is the slope of the first line and m_{2} is the slope of the second line.

Here, the line given is (y − 3) = (x − 4).

If we write it as y = mx + c, we get y = x - 1.

Hence, the slope of the line is 1. Let it be m_{1} = 1

Now, to find the slope of perpendicular line (m_{2}), we use m_{1}m_{2 }= -1

Thus, we get m_{2} = -1.