Answer     
Find out the  what is the surface area of the pyramid .
To proof
Formula
Surface area of a square pyramid

Where a is the base edge and h be the height .
As given
A square pyramid has a base with side lengths each measuring 40 inches. The pyramid is 21 inches tall, with a slant height of 29 inches.
i.e Base edge = 40 inches
Height =  21 inches    
 Put values in the above formula 

solving



= 1600 + 80 × 29
= 3920 inches²
Therefore the surface area of the pyramid is 3,920 inches²
Hence proved
 
 
        
                    
             
        
        
        
Answer:
Step-by-step explanation:
Given a general quadratic formula given as ax²bx+c = 0
To generate the general formula to solve the quadratic equation, we can use the completing the square method as shown;
Step 1:
Bringing c to the other side
ax²+bx = -c
Dividing through by coefficient of x² which is 'a' will give:
x²+(b/a)x = -c/a
- Completing the square at the left hand side of the equation by adding the square of half the coefficient x i.e (b/2a)² and adding it to both sides of the equation we have:
x²+(b/a)x+(b/2a)² = -c/a+(b/2a)²
(x+b/2a)² = -c/a+(b/2a)²
(x+b/2a)² = -c/a + b²/4a²
- Taking the square root of both sides 
√(x+b/2a)² = ±√-c/a + b²/√4a²
x+b/2a = ±√(-4ac+b²)/√4a²
x+b/2a =±√b²-4ac/2a
- Taking b/2a to the other side
x = -b/2a±√√b²-4ac/2a
Taking the LCM:
x = {-b±√b²-4ac}/2a
This gives the vertex form with how it is used to Solve a quadratic equation.
 
        
             
        
        
        
Answer:
0.164 = 16.4% probability that at least one color will be missing from the 10 selected balls.
Step-by-step explanation:
A probability is the number of desired outcomes divided by the number of total outcomes.
Determine the probability that at least one color will be missing from the 10 selected balls.
Red missing:
Each time, there are 55 + 25 = 80 non-red balls, out of 100. So, in each of the 10 trials, 80% = 0.8 probability of not picking a red ball. The probability that no red ball is picked is given by:
(0.8)^10 = 0.1074
White missing:
55 + 20 = 75 non-white balls, out of 100, in each trial. The probability that no white ball is picked is given by:
(0.75)^10 = 0.0563
Blue missing:
45 non-blue balls, out of 100. The probability that no blue ball is picked is given by:
(0.45)^10 = 0.0003
Total:
0.1074 + 0.0563 + 0.0003 = 0.164
0.164 = 16.4% probability that at least one color will be missing from the 10 selected balls.
 
        
             
        
        
        
The difference in gallons per day used is 3.6.
The formula to calculate a z-score is:

,
where X is the value used to calculate the score, μ is the mean and σ is the standard deviation.  We have the z-scores so we must work backward:

For both equations, we will cancel the 1.2 by multiplying both sides:

Now we will cancel 2.2 from both equations by adding it to both sides:
3.6+2.2=X-2.2+2.2     and       0+2.2=X-2.2+2.2
5.8=X     and       2.2=X
The difference in gas used per day would be given by
5.8-2.2 = 3.6.
 
        
        
        
Answer:
<em>r=3x</em>
Step-by-step explanation:
<u>The Volume of a Cone</u>
The volume of a cone of radius r and height h is:

We are given the volume of a cone is

Equating:

Multiplying by 3:

Simplifying by pi:

Since h=x:

Dividing by x:

Taking square roots:

Thus: r=3x