The vertex of the parabola is between the shortest line connecting its focus and directrix, so between (0, -4) and y = 4 is the point (0, 0), which is the vertex of the parabola. Also, this parabola faces downward.
The general formula for a parabola that faces downward is y = -4cx^2, where c is the distance from the vertex to either to focus or the parabola. Since c = 4, the equation is y = -16x^2, which is choice A.
The area of sector is 1.57 m²
<u>Explanation:</u>
Given:
Radius, r = 3 m
Central angle of a sector = 1/9π radians
Area of sector, A = ?
We know:
Area of sector, A = 
where,
α is the central angle in radians
On substituting the value we get:

Therefore, the area of sector is 1.57 m²
Answer: the number is 3.
Step-by-step explanation:
(x × 10) + 6 = 36
[(3) × 10] + 6 = 36
Answer:
To completely fill the sandbox will cost $56
Step-by-step explanation:
First, we calculate volume of the rectangular-shaped sandbox:

We know that density of sand is 100 pounds per cubic foot. Then, to fill the sand box that has a volume of 8 cubic foot, we calculate by rule 3:
1cubic foot..............100 pounds
8 cubic foot.............x pounds


We will need 800 pounds of sand to fill the sandbox, then we can calculate by rule 3 the number of bags needed and next the total cost of them:
50 pounds.......1bag
800 pounds.....x bags

To calculate the cost:
1 bag ..................$3.50
16 bags.................$x

To completely fill the sandbox will cost $56
Answer:
Concept: Basic Multiplication
- You have 3 1/4 which can be said in decimal form to be 3.25
- You multiply it by 3 to get 9.75 or 9 3/4
- Hence D
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