A scalene triangle is a triangle that has 3 sides that are all different lengths.
Let these letters represent the problem:
a = 8.7
b = side 2
c = side 3
P = 54.6
To find the perimeter, we just need to add all the sides [ P = a + b + c ]
So, put what we have in the formula above.
54.6 = 8.7 + b + c
Best of Luck!
 
        
                    
             
        
        
        
Total height of lumber, H = 10 1/2 feet = 21/2 feet .
Height of side panel, h = 5 2/3 feet = 17/3 feet .
Now, 
Extra lumber required, L = 2 × Height of side panel - Total height of lumber
![L=[2\times (\dfrac{17}{3})]-\dfrac{21}{2}\\\\L = \dfrac{5}{6}\ feet](https://tex.z-dn.net/?f=L%3D%5B2%5Ctimes%20%28%5Cdfrac%7B17%7D%7B3%7D%29%5D-%5Cdfrac%7B21%7D%7B2%7D%5C%5C%5C%5CL%20%3D%20%5Cdfrac%7B5%7D%7B6%7D%5C%20feet)
Therefore, extra lumber required is  feet.
 feet.
Hence, this is the required solution.
 
        
             
        
        
        
The answer for the given above is letter "a, -6r2s4t3". This is obtained by dividing 18 by -3 and subtracting the exponent below with that from above of the same variable. For r, subtract 2 from 4 to get 2. For s, subtract 1 from 5 to get 4 and lastly for t, subtract 3 from 6 to get 3.