What is the exponent on the 10 when 81,000,000 is converted to scientific notation?

Ineed with this problem 21 show steps

Sara made $253 for 11 hours of work. at the same rate how much would he make for 7 hours of work?

Which of these side lengths could form a triangle a) 2 cm , 2 cm , 4 cm b) 3 cm , 5 cm , 10 cm c) 3 cm , 4 cm , 5 cm d) 4 cm , 8 cm , 15 cm