Use a porportion to help better and speed up the process
First, you have to find what 80% of 15 is. In order to do that you have to change 80% percent to decimal, which would be .80. Then, multiply .80 and 15 to get 12. Subtract 12 from 15 and your answer is 3.
Answer:
Since the focus is at (-6,-11) and the directrix is at y=9:
The vertex is halfway between the focus and the directrix, so the vertex is at (-6,-1). (Draw this on graph paper if that doesn't make sense.)
The general form (conics form) of a parabola: 4p(y-k)=(x-h)^2 (vertex is (h,k) and "p" is the distance between the focus and vertex (or between vertex and directrix)).
(h,k) = (-6,-1)
p = 10 (distance between focus and vertex), so 4p = 40.
Therefore:
40(y+1)=(x+6)^2
Or if you need to rearrange to "vertex form": y=(1/40)(x+6)^2 - 1
Step-by-step explanation:
Let represents the total cost. We know for our problem that each yard of satin fabric costs $8.09, so yards will cost . similarly, each yard of cotton fabric costs $3.79, so yards will cost . We can also infer that the total cost, , will be the sum of the yards of satin fabric and the yards of cotton fabric, so:
Now, to determine the amount that Angeline would spend in all if she bought 5 yards of satin fabric and 8 yards of cotton fabric, we just need to replace and in our expression:
We can conclude that if Angeline would spend in all if she bought 5 yards of satin fabric and 8 yards of cotton fabric, she would spend $70.77
The bases of the trapezoid are 24 m and 9.6 m.
The area of the trapezoid is 141.12 m².