| Step | Hyp | Ref
| Expression |
| 1 | | df-br 4654 |
. . 3
  ⟂G      ⟂G    |
| 2 | | df-perpg 25591 |
. . . . . 6
⟂G        LineG  LineG   
   

      ∟G      |
| 3 | 2 | a1i 11 |
. . . . 5
 ⟂G        LineG 
LineG       

      ∟G       |
| 4 | | simpr 477 |
. . . . . . . . . . . 12
 
   |
| 5 | 4 | fveq2d 6195 |
. . . . . . . . . . 11
 
 LineG  LineG    |
| 6 | | isperp.l |
. . . . . . . . . . 11
LineG   |
| 7 | 5, 6 | syl6eqr 2674 |
. . . . . . . . . 10
 
 LineG    |
| 8 | 7 | rneqd 5353 |
. . . . . . . . 9
 
 LineG    |
| 9 | 8 | eleq2d 2687 |
. . . . . . . 8
 
  LineG 
   |
| 10 | 8 | eleq2d 2687 |
. . . . . . . 8
 
  LineG 
   |
| 11 | 9, 10 | anbi12d 747 |
. . . . . . 7
 
   LineG 
LineG  
     |
| 12 | 4 | fveq2d 6195 |
. . . . . . . . . 10
 
 ∟G  ∟G    |
| 13 | 12 | eleq2d 2687 |
. . . . . . . . 9
 
        ∟G 
      ∟G     |
| 14 | 13 | ralbidv 2986 |
. . . . . . . 8
 
  
      ∟G 

      ∟G     |
| 15 | 14 | rexralbidv 3058 |
. . . . . . 7
 
  

  

      ∟G 
            ∟G     |
| 16 | 11, 15 | anbi12d 747 |
. . . . . 6
 
    LineG 
LineG               ∟G    
     

      ∟G      |
| 17 | 16 | opabbidv 4716 |
. . . . 5
 
       LineG 
LineG       

      ∟G       
 
             ∟G      |
| 18 | | isperp.g |
. . . . . 6

TarskiG |
| 19 | | elex 3212 |
. . . . . 6
 TarskiG   |
| 20 | 18, 19 | syl 17 |
. . . . 5
   |
| 21 | | fvex 6201 |
. . . . . . . . 9
LineG   |
| 22 | 6, 21 | eqeltri 2697 |
. . . . . . . 8
 |
| 23 | | rnexg 7098 |
. . . . . . . 8
   |
| 24 | 22, 23 | mp1i 13 |
. . . . . . 7
   |
| 25 | | xpexg 6960 |
. . . . . . 7
 
     |
| 26 | 24, 24, 25 | syl2anc 693 |
. . . . . 6
     |
| 27 | | opabssxp 5193 |
. . . . . . 7
                   ∟G   
   |
| 28 | 27 | a1i 11 |
. . . . . 6
    
 
             ∟G   
    |
| 29 | 26, 28 | ssexd 4805 |
. . . . 5
    
 
             ∟G      |
| 30 | 3, 17, 20, 29 | fvmptd 6288 |
. . . 4
 ⟂G     
 
             ∟G      |
| 31 | 30 | eleq2d 2687 |
. . 3
     ⟂G   
    
 
             ∟G       |
| 32 | 1, 31 | syl5bb 272 |
. 2
   ⟂G  
                      ∟G       |
| 33 | | isperp.a |
. . 3
   |
| 34 | | isperp.b |
. . 3
   |
| 35 | | ineq12 3809 |
. . . . 5
 
       |
| 36 | | simpll 790 |
. . . . . 6
         |
| 37 | | simpllr 799 |
. . . . . . 7
           |
| 38 | 37 | raleqdv 3144 |
. . . . . 6
          
      ∟G 

      ∟G     |
| 39 | 36, 38 | raleqbidva 3154 |
. . . . 5
        

      ∟G 


      ∟G     |
| 40 | 35, 39 | rexeqbidva 3155 |
. . . 4
 
              ∟G 
            ∟G     |
| 41 | 40 | opelopab2a 4990 |
. . 3
 

         
             ∟G         
      ∟G     |
| 42 | 33, 34, 41 | syl2anc 693 |
. 2
                        ∟G         
      ∟G     |
| 43 | 32, 42 | bitrd 268 |
1
   ⟂G  
            ∟G     |