If n m , find the value of x and the value of z

15 points ! ~ see if you know the answer to both you!

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 sin 7x/4 ? i need on this urgent trig