The 3rd one 
Pure tessellations- uses only one shape
        
             
        
        
        
The answer is <span>B. The cable company decrease the monthly charge by 20%</span>
        
             
        
        
        
To solve this problem, we need to know that 
arc length = r θ  where θ is the central angle in radians.
We're given
r = 6 (units)
length of minor arc AB = 4pi
so we need to calculate the central angle, θ
Rearrange equation at the beginning,
θ = (arc length) / r = 4pi / 6 = 2pi /3
Answer: the central angle is 2pi/3 radians, or (2pi/3)*(180/pi) degrees = 120 degrees
        
                    
             
        
        
        
Answer:
To prove:
X+Y.Z=(X+Y).(X+Z)
Taking R.H.S 
= (X+Y).(X+Z)
By distributive law
= X.X+X.Z+X.Y+Y.Z --- (1)
From Boolean algebra
X.X = X
X.Y+X.Z = X.(Y+Z)
Using these in (1)
=X+X(Y+Z)+Y.Z
=X(1+(Y+Z)+Y.Z --- (2)
As we know (1+X) = 1
Then (2) becomes
=X.1+Y.Z
=X+Y.Z
Which is equal to R.H.S
Hence proved,
X+Y.Z=(X+Y).(X+Z)
 
        
             
        
        
        
1000 square feet of wheat produces 250 pounds of grain.