ban chiu kho tu ve hinh nhe!a,Trong mp$(ABN)$: $ME\cap BN=J\Rightarrow \left\{ \begin{array}{l} J\in ME\\ J\in BN\subset (BCD) \end{array} \right.\Rightarrow J=ME\in (BCD)$b,$*$ta co $Q\in (EMQ)\cap ( BCD) (1)$ Trong mp $(BCD):CD\cap QJ=P\Rightarrow P\in (EMQ)\cap (BCD) (2)$Tu $(1)$ va $(2)$$:(EMQ)\cap (BCD)=PQ$$*M\in (EMQ)\cap (ABD) $Trong mp$(ACD):EP\cap AD=F\Rightarrow F\in (EMQ)\cap (ABD)$$\Rightarrow (EMQ)\cap (ABD)=FM$c,Ta co:$\left\{ \begin{array}{l} (QME)\cap (ABC)=QM\\(QME)\cap (BCD)=QP\\(QME)\cap(ACD)=FP\\ (QME)\cap(ABD)=MF \end{array} \right.$Vay thiet dien cat boi mp$(QME)$la tu giac $FMQP$
ban chiu kho tu ve hinh nhe!a,Trong mp$(ABN)$: $ME\cap BN=J\Rightarrow \left\{ \begin{array}{l} J\in ME\\ J\in BN\subset (BCD) \end{array} \right.\Rightarrow J=ME\in (BCD)$b,$*$ta co $Q\in (EMQ)\cap ( BCD) (1)$ Trong mp $(BCD):CD\cap QJ=P\Rightarrow P\in (EMQ)\cap (BCD) (2)$Tu $(1)$ va $(2)$$:(EMQ)\cap (ACD)=PQ$$*M\in (EMQ)\cap (ABD) $Trong mp$(ABD):EP\cap AD=F\Rightarrow F\in (EMQ)\cap (ABD)$$\Rightarrow (EMQ)\cap (ABD)=FM$c,Ta co:$\left\{ \begin{array}{l} (QME)\cap (ABC)=QM\\(QME)\cap (BCD)=QP\\(QME)\cap(ACD)=FP\\ (QME)\cap(ABD)=MF \end{array} \right.$Vay thiet dien cat boi mp$(QME)$la tu giac $FMQP$
ban chiu kho tu ve hinh nhe!a,Trong mp$(ABN)$: $ME\cap BN=J\Rightarrow \left\{ \begin{array}{l} J\in ME\\ J\in BN\subset (BCD) \end{array} \right.\Rightarrow J=ME\in (BCD)$b,$*$ta co $Q\in (EMQ)\cap ( BCD) (1)$ Trong mp $(BCD):CD\cap QJ=P\Rightarrow P\in (EMQ)\cap (BCD) (2)$Tu $(1)$ va $(2)$$:(EMQ)\cap (
BCD)=PQ$$*M\in (EMQ)\cap (ABD) $Trong mp$(A
CD):EP\cap AD=F\Rightarrow F\in (EMQ)\cap (ABD)$$\Rightarrow (EMQ)\cap (ABD)=FM$c,Ta co:$\left\{ \begin{array}{l} (QME)\cap (ABC)=QM\\(QME)\cap (BCD)=QP\\(QME)\cap(ACD)=FP\\ (QME)\cap(ABD)=MF \end{array} \right.$Vay thiet dien cat boi mp$(QME)$la tu giac $FMQP$