You can quickly solve this if you know the trig ratio for the special angles. 45 degrees is one of the special angles. In this case you can use the adjacent side and hypotenuse lengths to find s, so cos is the trig ratio you want.
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.
