The amount of money a consumer has available to spend shifts his budget line in a parallel direction but does not affect its slope.

In math and statistics, you may occasionally need to calculate the slope of a line generated by coordinates in the (x,y) format. The slope is a value that indicates the rate at which the y value ...

Learn how to find equations of parallel lines, work out the gradient of perpendicular lines, and prove that given lines are parallel or perpendicular.

So tell us, did you spot the horizontal lines parallel or do they slope down in this optical illusion? Check A 900-Year-Old Optical Illusion revealing your Personality Traits ...