When I input segment CD onto a graph, I get -0.4 as the slope or 15/-6. If the lines were parallel, they would need to have the same slope which they do not have. If they were perpendicular, they would need to have different slopes so, -2/5 and 5/2 which they do not. That leaves us with the only option of neither.
Multiply the cost of an item or service by the sales tax in order to find out the total cost. The equation looks like this: Item or service cost x sales tax (in decimal form) = total sales tax. Add the total sales tax to the Item or service cost to get your total cost.