[填空题]
A rock is dropped from a sezrw9 7chrx1+a a cliff, and the sound of it strikingpu0twmx 1tx;ibz1aq0 4 3vjb6ces f1 . the ocean is heard 5.2 s later. m10bs1b e.zc 3wf xa 014jpqvx;tiut6If the speed of sound is $340 \; m/s$, how high is the cliff? $m$
