The circumference of a circle 15 pi centimetres. What is the area of the circle in terms of pi

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?

Proportions in triangles solve for x

Which expression gives the exact value of x?