The answer is: c 
Explination 30-9=21
        
             
        
        
        
5x + 4x = 720
9x = 720 (divide by 9)
X= 80
In order to get the bigger ratio, which is 5, you would substitute x for 80. (I'm bad at explaining)
Work:
5(80)= 400
        
             
        
        
        
Answer:
Perimeter = 122 cm or 1.22 m
Step-by-step explanation:
The complete question with image is attached.
We know the perimeter is the sum of all the sides.
Since it's already given that one side is 30.5 and we know it is a square, so perimeter would be sum of all the 4 sides [each 30.5 cm].
Perimeter = 30.5 + 30.5 + 30.5 + 30.5 = 122 cm
Also, to get the answer in meters, we need to know that 100 cm = 1 m, hence
We got to divide by 100 to get our answer in meters, so
122/100 = 1.22 meters
Hence
Perimeter = 1.22 m
 
        
             
        
        
        
Answer:
5.0 ft - 5.6 ft
Step-by-step explanation:
Given that the structure is to be made using two 12 foot boards, then we expect the total perimeter to be equal to (2*12)= 24 ft.
Using the angle of elevation, 40° and the width of 8 ft then you can apply the formula for tangent of a triangle where ;
Tan α = opposite side length/adjacent length
Tan 40°= h/8
h= 8 tan 40° = 6.71 ft
Applying the cosine of an angle formula to find the length of the sliding side
Cosine β = adjacent length /hypotenuse
Cosine 40°= 8/ sliding side length
sliding side length = 8/cosine 40° =10.44 ft
Checking  the perimeter = 10.44 +8+6.71= 25.15 ft
This is more than the total lengths of the boards, so you need to adjust the height as;
24 - 18.44 = 5.56 ft ,thus the height should be less or equal to 5.56 ft
h≤ 5.6 ft