[填空题]
Two drones are being flog k;*3)huaessawd(rzj;cp 52 d; l ,vhwn in a park. Drone A starts at point P kvq 7,jnkis2l4v+9et and travels towards p94tqj+kskel v,27in voint Q in a straight line on a true bearing of $115^{\circ}$ at a speed of $2.5ms^{-1}$. The distance from P to Q is 800m.
Drone B starts at point Q and travels towards point R in a straight line on a true bearing of $215^{\circ}$ at a speed of $7.5ms^{-1}$ .
These two paths are shown on the diagram below.
1.Find the acute angle $\mathrm{P}\hat{\mathrm{Q}}\mathrm{R}$. $^{\circ}$
2.Find the distance between Drone A and Drone B after 4 minutes, rounding your answer to the nearest metre. m
