Answer:
20
23 is between 20 and 30, but it's closer to 20. So 23 is rounded down to 20.
<h2>Explanation:</h2>
Here we need to solve some expressions. Remember the following rules:
Then, from the left side:
from the right side:
Call the length a, the width b
Perimeter = (a+b) x 2
And since we have (a+b) x 2 = 43.6, a + b = 43.6 : 2 = 21.8
a + b = 21.8
a - b = 7
-> a + b + (a - b) = 28.8
2a = 28.8
a = 14.4
b = 7.4
So, the area of the rectangle is 14.4 x 7.4 = 106.56
Vertex: (-5,-2); parabola opens up;
General form of the equation for a vertical parabola opening up is:
y-k = a(x-h)^2; knowing that the vertex is at (-5,-2), we can write:
y+2 = a(x+5)^2. We need to find the value of the coefficient a.
From the graph we see that y is 10 when x is approx. -1 3/4 (or -7/4).
subst. these values into y+2 = a(x+5)^2, we get:
10 + 2 = a(-7/4 + 5)^2, or 12 = a(13/4)^2, or 1 = a(169/16).
Solving for a: a = 16/169 = 0.09, or approx 16/160, or 1/10. Unfortunately, this is not close to any of the four answer choices.
I thought it best to try again, and fortunately my second try was correct:
10+2 = a(13/4)^2, or (169/16)a. Thus, 12 = a(169/16)
12
Solving for a: a = ------------- = 1.14. The answer choice closest to this is 1.
169/16
Answer A is correct.
