To solve this we need to use this formula:


Well some equations might not make scene if not put in different ways so like lets say there was a problem and the only you could solve it was in decimals I hope that makes scene if not message me and ill explain better.:)
Answer:
a plane figure with three straight sides and three angles.
Step-by-step explanation:
10% - $4.50
20% - $9
5% - $2.25