Set this up as a proportion with the model stuff on top and actual building stuff on bottom.  

.  Cross multiply to get x = 780.  The actual building is 780 inches.  In feet that is 65.
 
        
        
        
Answer:
87
Step-by-step explanation:
348 divided by 4
 
        
                    
             
        
        
        
The answer is:  " 91 " .   
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                    →    " B = 91 " . 
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Explanation:
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Given:  
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    "  A +  B = 180 " ;
  "A =  -2x + 115 " ;   ↔  A =  115 − 2x ;  
  "B = - 6x + 169 " ;  ↔  B = 169 − 6x ;  
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METHOD 1)
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Solve for "x" ; and then plug the solved value for "x" into the expression given for "B" ; to  solve for "B"
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(115 − 2x) + (169 − 6x) = 
  115 − 2x + 169 − 6x = ?
→ Combine the "like terms" ;  as follows:
      + 115 + 169 = + 284 ; 
 − 2x − 6x = − 8x ; 
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And rewrite as:
 " − 8x + 284 " ; 
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   →  " - 8x + 284 = 180 " ; 
Subtract:  "284" from each side of the equation:
  →  "  - 8x + 284 − 284 = 180 − 284 " ; 
to get:
 →  " -8x = -104 ; 
Divide EACH SIDE of the equation by "-8 " ; 
    to isolate "x" on one side of the equation; & to solve for "x" ; 
→ -8x / -8 = -104/-8 ; 
→  x = 13
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Now, to find the value of "B" :
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  "B = - 6x + 169 " ;  ↔  B = 169 − 6x ;  
↔  B = 169 − 6x ;  
         = 169 − 6(13) ;   ===========> Plug in our "solved value, "13",  for "x" ;
         = 169 − (78) ; 
         = 91 ;
   B   = " 91 " .
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The answer is:  " 91 " . 
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     →     " B = 91 " . 
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Now;  let us check our answer:
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               →   A + B = 180 ;  
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Plug in our "solved answer" ; which is "91", for "B" ;  as follows:
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→  A + 91 = ? 180? ;  
↔  A = ? 180 − 91 ? ; 
→  A = ?  -89 ?  Yes!
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→  " A =  -2x + 115 " ;   ↔  A =  115 − 2x ;  
Plug in our solved value for "x"; which is: "13" ; 
" A = 115 − 2x " ; 
→  A = ? 115 − 2(13) ? ;
→  A = ? 115 − (26) ? ; 
→  A = ? 29 ? Yes!
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METHOD 2)
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Given:  
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    "  A +  B = 180 " ;
  "A =  -2x + 115 " ;   ↔  A =  115 − 2x ;  
  "B = - 6x + 169 " ;  ↔  B = 169 − 6x ; 
→  Solve for the value of "B" :
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 A + B = 180 ;  
→ B = 180 − A ; 
→ B = 180 − (115 − 2x) ; 
→ B = 180 − 1(115 − 2x) ;  ==========> {Note the "implied value of "1" } ; 
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Note the "distributive property" of multiplication:__________________________________________________  a(b + c)  = ab +  ac ;  <u><em>AND</em></u>:
  a(b − c)  = ab − ac .________________________________________________________
Let us examine the following part of the problem:
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              →      " − 1(115 − 2x)  " ; 
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→  "  − 1(115 − 2x) " = (-1 * 115) − (-1 * 2x) ;
                                =  -115 − (-2x) ;
                          
                                =  -115  +  2x ;        
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So we can bring down the:  " {"B = 180 " ...}"  portion ; 
→and rewrite:
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→  B = 180 − 115 + 2x ; 
→  B = 65 + 2x ; 
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Now;  given:   "B = - 6x + 169 " ;  ↔  B = 169 − 6x ; 
→ " B =  169 − 6x  =  65 + 2x " ; 
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→  " 169 − 6x  =  65 + 2x "
Subtract "65" from each side of the equation;  & Subtract "2x" from each side of the equation:
→  169 − 6x − 65 − 2x  =  65 + 2x − 65 − 2x ; 
to get:
→   " - 8x + 104 = 0 " ; 
 
Subtract "104" from each side of the equation:
→   " - 8x + 104 − 104 = 0 − 104 " ;
to get: 
→   " - 8x = - 104 ;
Divide each side of the equation by "-8" ; 
   to isolate "x" on one side of the equation; & to solve for "x" ; 
→  -8x / -8  = -104 / -8 ; 
to get:
→  x =  13 ; 
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Now, let us solve for:  " B " ;  → {for which this very question/problem asks!} ; 
→  B = 65 + 2x ;  
Plug in our solved value, " 13 ",  for "x" ; 
→ B = 65 + 2(13) ; 
        = 65 + (26) ;  
→ B =  " 91 " .
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Also, check our answer:
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Given:  "B = - 6x + 169 " ;   ↔  B = 169 − 6x = 91 ; 
When "x  = 13 " ; does: " B = 91 " ? 
→ Plug in our "solved value" of " 13 " for "x" ; 
      → to see if:  "B = 91" ; (when "x = 13") ; 
→  B = 169 − 6x ; 
         = 169 − 6(13) ; 
         = 169 − (78)______________________________________________________
→ B = " 91 " . 
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Answer: 10ft
Step-by-step explanation:
Using the Pythagorean theorem (a² + b² = c²) you would end up with an equation like this: 36 + 64 = 100. You would then square root 100 and the answer would be 10 ft