[填空题]
The following diagrajw/ fn su)xzlw(n f0s qjp*8(/2bq6q 7qpvbg3m shows a circle with centre O and radius 7.2 cm.
Points $\mathrm{A}, \mathrm{B}$ lie on the circle and $\mathrm{AO} \mathrm{B}=1.3$sv radians.
1. Find the length of:
1. minor arc A B ;
2. chord A B .≈ cm
2. Find the area of the shaded region.≈ $cm ^2$
