If nthe shop has a mark up rate of 50% and they cost 300 to buy you multiply 300 by 50% convert 50% to decimal
so you do .5*300=150
then you add 150 to 300 which means that the shop sells the skis for 450 dollars.
slope = rise over run = y/x
A (-1,3) slope = 3/-1 = -3
B (1,2) slope = 2/1 = 2
C (-3,-1) slope = -1/-3 = 1/3
2 lines need to be negative reciprocals in order to be a right triangle
negative reciprocal of -3 is 1/3
so this is a right triangle