An archway in front of a school is in the shape of a parabola. The top of the arch is the vertex (0,0). The school seal is at the focus, 2.5 feet below the vertex, and the arch is 18 feet wide at the ground

a) The equation of the arch is .

b) The height of the arch from the ground is 810 feet.

Step-by-step explanation:

Statement is incomplete. Complete statement is:

An archway in front of a school is in the shape of a parabola. The top of the arch is the vertex (0,0). The school seal is at the focus, 2.5 feet below the vertex, and the arch is 18 feet wide at the ground.

Write an equation  that represents the arch.

What is the height from the top of the arch to the  ground?

a) Write an equation that represents the arch.

According to the statement, the archway is a vertical downward parabola. From Analytical Geometry we know that parabolas are represented by the following equation in standard form:

(Eq. 1)

Where:

- Distance between vertex and focus, measured in feet.

- Independent variable, measured in feet.

- Dependent variable, measured in feet.

, - Coordinates of the vertex, measured in feet.

If we know that , and , then the equation that represents the arch:

The equation of the arch is .

b) What is the height from the top of the arch to the  ground?

Given that parabola is a symmetrical curve, we determine the vertical position at the base of the arch ():

Then, the height of the arch from the ground is given by this difference:

The height of the arch from the ground is 810 feet.

step-by-step explanation:

the options are kind of confusing. i can tell you what i see going on here when i look at the graph.

the class and exam medians are closely related, and it looks like the low outlier on the exam did pull the median lower. [tex][/tex]

let's cover over the formula of the vertex:

y = a(x – h)^2 + k

in this formula, (h,k) are the vertex, always remember that the positive or negative value of the vertex is based on the sign it has.

for example, if the vertex is -3,-6 then both the x and y value would have the positive sign attached to it and if it were a positive x and y value, then a negative sign would be attached to it.

with that being said, for our problem the x value is a positive one so we are looking for a number with a negative sign next to it, in this case the first and second choice.

however, for the first answer choice it isn't quite part of the formula so we know that the answer choice correctly displays the x value.

to confirm, we can see if the -1 fits correctly with the second answer choice, and as mentioned above a negative number will have a positive sign attached to it. so, for our problem we can see that -1 has been changed to +1, so we can confirm that the second answer choice is correct.

hence, our final answer is y=(x - 1)^2 + 1