Which of the following best describes the focus of a parabola? O A. A single line that is the same distance from the parabola as the
directrix is from the parabola
B. A single line that is half the distance from the parabola as the
directrix is from the parabola
C. A single fixed point that is the same distance from the parabola as
the directrix is from the parabola
D. A single fixed point that is half the distance from the parabola as
the directrix is from the parabola

Explanation:

We are told that quadrilateral ABCD is similar to quadrilateral EFGH.

The order of the four letter sequence is important.

Therefore, AB and EF are corresponding sides.

So AB = 10 and EF = x pair up together. We can form the ratio AB/EF which becomes 10/x.

The diagram shows that AD = 8. Notice that A and D are the first and last letters of ABCD. The first and last letters of EFGH are E and H. We can see that AD and EH correspond to one another because of this.

AD = 8 and EH = 6 forming the ratio AD/EH = 8/6

Because the quadrilaterals are similar, the corresponding ratios must be the same. Therefore, AB/EF is the same as AD/EH.

Let's set up a proportion to solve for x

AB/EF = AD/EH

10/x = 8/6

10*6 = x*8

60 = 8x

8x = 60

x = 60/8

x = 7.5  Answer is choice D