I'm having an issue trying to find the length of sides x and y, the question says to use the pythagorean theorem

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 difference between the predicted value and the actual value

If rt is greater than ba, which statement must be true ?