HELP ME PLEASE! how do you write 9.1 x 10^ -3 ?

What is the area of a pizza with a radius of 40 cm leave the answer in terms of π to find your exact answer 40π cm² 1600π cm² 800π cm² 80π cm² π=pi

The ratio of the measures of the three angles in a triangle is 2: 9: 4. find the measures of the angels

The width of a rectangle is half as long as the length. the rectangle has an area of 18 square feet. what are the length and width of the rectangle?