I need help with this please

In the proof of the triangle angle sum theorem, you must draw an auxiliary line. which construction must you use to draw this line?

12. the amount of money in a bank account decreased by 21.5% over the last year. if the amount of money at the beginning of the year is represented by ‘n', write 3 equivalent expressions to represent the amount of money in the bank account after the decrease?

How many of the 250 grandparents in the population would you expect to prefer online shopping with merchant a? merchant a: 4 merchant b: 6 merchant c: 2 merchant d: 3 other: 5 none: 5 answer choices: a.about 4 b.about 8 c.about 40 d.about 21