[填空题]
During a hiking trip, Jim t . pv0-thyukhl:k 73istopped and checked his compass for djbtb5gt,:1p. .rbjjpdn4 s ,yirections. The compass has a circular face with centre at O and the diameter of ys1p r jj4,p:b.jbttdnb, g5.20 cm. The needle of the compass is at an angle of $\theta$ to the East of North, covering an arc length of $l$, as illustrated in the diagram below.
1.Determine the circumference of the face of the compass. cm
2.Using the diagram, write down the size of the angle $\theta$ in degrees. $^{\circ}$
3.Calculate the arc length, $l$. cm
4.Calculate the total area of the shaded sectors on the diagram. $cm^2$
