Can u help me plz and thank u

Can someone me with my hwplz(only the circled ones)

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?

What is the base of 1/9 to the power of 2