The diagram shows a sector of a circle of radius r cm containing angle Ө radians. The area of the sector is Acm2 and the perimeter of the sector is 50 cm.
a. Find Ө in terms of r.
b. Show that A = 25r – r2
Frank and Marie set sail from the same point. Frank is sailing in the direction S5 °E. Marie is sailing in the direction S9°W. After 3 hours, Marie was 2 miles due west of Frank. How far had Marie sailed? Round to 4 decimal places.