What is the gradient of a line
perpendicular to a line with a gradient
of 5

-1/5

Step-by-step explanation:

When a line is perpendicular to another line, it's gradient will be a reciprocal.

To calculate the reciprocal of a number you have to flip the fraction the other way around.

So, in the case our current gradient is 5/1 (5/1 is the same as just 5) and we need to flip in over to get 1/5, which is our new gradient.

The final step is to make the number negative because the line is going down. This gives us the final answer of -1/5.