Each of the four sides of a swimmimg pool measures 9 meters. The pool is 5 meters deep. How much water will be needed to fill it
1 answer:
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Answer:
Step-by-step explanation:
Let's solve for in the first equation and then solve for
in the second equation.
I will then use the following identity to get right of the parameter, :
(Pythagorean Identity).
Let's begin with .
Subtract 2 on both sides:
Divide both sides by -3:
Now time for the second equation, .
Subtract 1 on both sides:
Divide both sides by 4:
Now let's plug it into our Pythagorean Identity:
Focus has coordinates (0, a)
a = -3
Thus, 4a = 4(-3) = -12
Because a is negative, we know it will be a concave down or concave left parabola. Hence, A and D can be eliminated. And we know it has to be B because the directrix is the horizontal line y = 3. Hence, the equation of the parabola becomes:
or 
a = -3
Thus, 4a = 4(-3) = -12
Because a is negative, we know it will be a concave down or concave left parabola. Hence, A and D can be eliminated. And we know it has to be B because the directrix is the horizontal line y = 3. Hence, the equation of the parabola becomes: