If 2/3 of the distance from the y-axis to point A (−30, −45) is equal to 1/4 of the distance from the x-axis to point B(5a, 2a), where a > 0, what is the value of a?

Respuesta :

Answer:

The value of a is 80

Step-by-step explanation:

The distance of a point [tex](x_o,y_0)[/tex] from the y-axis can be written as [tex]d_y=|x_o|[/tex]  because the x-coordinate of the y-axis is zero.

Similarly, the distance of a point  from the x-axis can be written as [tex]d_x=|y_0|[/tex]

since the y-coordinate of the x-axis is zero.

In this problem:

- The distance of the point A (−30, −45) from the y-axis can be written as

[tex]d_A=|-30|=30[/tex]

- The distance of point B (5a,2a) from the x-axis can be written as

[tex]d_B=|2a|=2a[/tex]

Since [tex]a>0[/tex]

We are told that 2/3 of the distance from the y-axis to point A (−30, −45) is equal to 1/4 of the distance from the x-axis to point B(a, a), which means

[tex]\frac{2}{3}d_A=\frac{1}{4}d_B[/tex]

Therefore,

[tex]\frac{2}{3}(30)=\frac{1}{4}(2a)[/tex]

And solving for a,

[tex]20=\frac{1}{2}a\\a=40[/tex]