Someone help me with this pls

Select all the correct answers. what is 221,000,000,000,000,000,000 expressed in scientific notation?

This figure consists of a rectangle and semicircle. what is the perimeter of this figure use 3.14 for pi 60.84m 72.84m 79.68m 98.52m

Find the measure of the interior angles of the following regular polygons: a triangle, a quadrilateral, a pentagon, an octagon, a decagon, a 30-gon, a 50-gon, and a 100-gon.