Write 102,800,000 in scientific notation

Plz i want answer and i would appreciate it is is a b c or d

The radius of the circle is 4 cm and the measure of the central angle is 90° the area of the sector with a central angle measuring 90° and radius of length 4 cm is vt cm the triangle in the sector is 4 cm the area of the triangle is v/cm² the area of the segment of the circle is (471 - ) cm?

Angles r and s are complementary. the measure of angle r is 31 degrees. which equation can be used to find angle s?