are two lines that intersect at right angles are perpendicular?

http://www.mathopenref.com/perpendicular.html

Yes, two lines that intersect at a right angle are considered perpendicular.

To determine if two lines are perpendicular, you can use their slopes. The slope of a line represents how steeply the line rises or falls as it moves horizontally.

If two lines are perpendicular, their slopes will be negative reciprocals of each other. In other words, if the slope of one line is m, then the slope of the other line will be -1/m.

So, to check if two lines are perpendicular, you need to find their slopes and calculate their negative reciprocals. If the negative reciprocals are equal, then the lines are perpendicular.

Alternatively, you can also check if the product of their slopes is -1. If the product is -1, then the lines are perpendicular.

Remember, for two lines to be considered intersecting at a right angle, they must have one point of intersection and the angle formed at that point must be equal to 90 degrees (a right angle).