Answer :
x = 53.85
Step by step explanation:
If 78% of x (some numbers) is equal to 42, then we must set this as an equation to find it.
1) Rewriting 78% as a fraction and considering that when we say 78% of some number (x) we mean a product.
78% = 78/100 ➡️ 78/100x = 42
2) Then we can go on :
100 * 78/100x = 42 * 100
78x = 4200
78x/78 = 4200/78 ➡️ x = 53.85
3) Alternatively, simply dividing 42 by 0.78 (78%) would come to the same result :
42/0.78 = 53.85
It's going to be kind of crazy, but you need to use Pythagorean's Theorem for this. That will look like this:

. FOIL out the left side to get

. FOIL out the first of the 2 expressions on the right to get

, and the second of the 2 to get 4x. Our equation now looks like this:

. Combine like terms to get an equation that still has square roots in it that we have to deal with:

and

. We will square both sides to get rid of the square root sign.

. This is a polynomial now that can be factored to solve for x. Bring the 2x over by subtraction and set the polynomial equal to 0.

. Factor out an x, leaving us with x(x-2)=0. That means that x = 0 or x - 2 = 0 and x = 2. Of course if we are solving for the length of a side we know it can't have a side length of 0, so it must have a side length that is a multiple of 2. x = 2
Please find the attachment below for the solution...
Answer:
a) A. The population must be normally distributed
b) P(X < 68.2) = 0.7967
c) P(X ≥ 65.6) = 0.3745
Step-by-step explanation:
a) The population is normally distributed having a mean (
) = 64 and a standard deviation (
) = 
b) P(X < 68.2)
First me need to calculate the z score (z). This is given by the equation:
but μ=64 and σ=19 and n=14,
and 
Therefore: 
From z table, P(X < 68.2) = P(z < 0.83) = 0.7967
P(X < 68.2) = 0.7967
c) P(X ≥ 65.6)
First me need to calculate the z score (z). This is given by the equation:
Therefore: 
From z table, P(X ≥ 65.6) = P(z ≥ 0.32) = 1 - P(z < 0.32) = 1 - 0.6255 = 0.3745
P(X ≥ 65.6) = 0.3745
P(X < 68.2) = 0.7967
All triangles angles in the inside add up to 180, so 180-76-72=32