The perimeter is twice the sum of the length and the width:

The area is the product of the dimensions:

So, the system is

 
        
             
        
        
        
OK.  I used my calculator to evaluate sec(85 degrees).
My calculator doesn't have a "sec" button on it.  
But I remembered that
           sec of an angle = 1 / (cosine of the same angle) .
So I used my calculator to find cos(85), and then I hit the 
" 1/x " key, and got 11.474, which I knew to be sec(85).
        
             
        
        
        
Answer:
[(1/12)(5/5) + (1/20)(3/3)](x hours) = 1
(5/60 + 3/60)x = 1
(8/60)x = 1 we can reduce 8/60 by dividing out a 4
(2/15)x = 1 x both sides by 15/2
x = 15/2
x = 7 1/2 or 7.5 hours
 
 
        
             
        
        
        
Answer:
4046.56 cm3
Step-by-step explanation:
The base is made by 5 isosceles triangles, with one side of 14 cm, and the opposite angle of 
. Each of the other angle is 
. From there, you can calculate the height of each base triangle as in 
 or 9.634...cm.
Your volume will be 