If the area of triangle ABC is D give the expressions that complete the equation for the measure of angle C

Question and answers are in the attached picture. you so much in advance.

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?

In the diagram of circle a what is m