# Math Help - slope

1. ## slope

See attachment grab a shovel and help unbury the dyeing.

2. Originally Posted by jeilynn
See attachment grab a shovel and help unbury the dyeing.
Hello, jeilynn,

the slope m of a straight line between two points of this line is calculated by:
Code:
      y1 - y2
m =  -----------
x1 - x2
1) slope (AB):

m_(AB) = (1 - (-1))/(-3 - 2) = 2/(-5) = -2/5

2) slope (BC):

m_(BC) = (-1 - 4)/(2 - 4) = (-5)/(-2) = 5/2

Because m_(Ab) * m_(BC) = -2/5 * 5/2 = -1 the lines (AB) is perpendicular to line (BC)