Mary is explaining the angle relationship of the interior angles of triangles to a coworker. She states that the angles should always add up to 180°. How can Mary prove that this is true? (Hint: Imagine taking the angles and putting them side by side.)

Plz answer asap! i will reward brainliest and 12 points for these three questions!take notice: these three questions are completely different! 1) what is the percentage of sugar in the syrup made of 10 kg of water and 4 kg of suugar? 2) what was the original price if after 10% discount it became $450? 3) at first a price was decreased by 12%, then it was disounted again by an additional 5%. what is the percent of the total discount? , and remeber i will award brainliest and 12 points!