(1)作PE,PD分别垂直于BC,BA,设PF垂直面ABC于F,连接EF,FD,FC,
∵EP⊥CE,PF⊥CE,
∴CE⊥面PEF,∴CE⊥EF
同理,CD⊥DF
∵∠C是直角,
∴四边形ECDF是矩形
∴EC=DF
Rt△PEC中,PE=6
| 10 |
242−(6
|
| 6 |
Rt△PDF中,PF=
(6
|
(2)由题意,PF垂直面ABC于F,∠PCF为直线PC与面ABC所成的角.
∵sin∠PCF=
| PF |
| PC |
| 1 |
| 2 |
即直线PC与面ABC所成的角为30°
| 10 |

(1)作PE,PD分别垂直于BC,BA,设PF垂直面ABC于F,| 10 |
242−(6
|
| 6 |
(6
|
| PF |
| PC |
| 1 |
| 2 |