sellers buy items from manufacturers and need a profit whenever they sell a product. Therefore, they cannot allow the cost price to equal the selling price. So they add an extra amount, called a markup, to the cost price to arrive at the selling price.
It's 82 degrees. Subtract your minor arc (98) by 360 to get your major arc, which is 262. Then, subtract 98 (minor arc) from 262 (major arc), which gives you 164. Finally, divide 164 by 2 to get angle ABC.