Point (5 5/8, 2 1/4) lies on a line that represents a proportional relationship. Write an equation for this relationship. What is the proportionality?

The point (6 1/2, y) also lies on the line. What is the y-coordinate of the point?

Respuesta :

Answer:

The equation is [tex]y=0.4x[/tex]

The y coordinate of point (6 1/2, y) is y=2 3/5

Step-by-step explanation:

Let us first convert everything to decimal numbers:

[tex](5\frac{5}{8},2\frac{1}{4} )=(5.625,2.25)[/tex]

[tex]6\frac{1}{2} =6.5[/tex]

In a proportional relationship

[tex]\frac{y_1}{x_1} =\frac{y_2}{x_2}[/tex]

For the set of points [tex](5\frac{5}{8},2\frac{1}{4} )[/tex]

[tex]\frac{y_1}{x_1}=\frac{2.25}{5.625}=0.4[/tex]

now this must equal [tex]\frac{y_2}{x_2}[/tex]:

[tex]0.4=\frac{y_2}{x_2}=\frac{y_2}{6.5}\\y_2=0.4*6.5=2.6\:\:\:or\:as\:a\:mixed\:fraction\:\:\:2\frac{3}{5}[/tex]

Now for a proportional relationship the equation is

[tex]y=kx[/tex]

where [tex]k[/tex] is the common ratio between [tex]x[/tex] and [tex]y[/tex] (officially called the 'constant of proportionality').

Now in our case the common ratio is 0.4; therefore

[tex]y=0.4x.[/tex]