Both circle Q and circle R have a central angle measuring 75°. The ratio of circle Q's radius to circle R's radius is 3 4 . Which ratio represents the area of the sector for circle Q to the area of the sector for circle R? A) 16 9 B) 2 5 C) 3 4 D) 9 16

Respuesta :

Answer:

D) 9 : 16

Step-by-step explanation:

Given,

Central angle for circle Q = Central angle for circle R = 75°

Ratio of the radii of circle Q to circle R = [tex]\frac{3}{4}[/tex]

We have to find the ratio of the areas of the sector for circle Q to the sector for circle R.

Solution,

Since we know that the formula for Area of sector is [tex]\frac{\pi r^2\theta}{360}[/tex].

So the ratio of the areas of sectors for circle Q to circle R;

[tex]Ratio=\frac{\frac{\pi r_1^2\theta}{360}}{\frac{\pi r_2^2\theta}{360}}[/tex]

Here the central angle(θ) is equal for both circles.

And also π and 360° is equal, so we can cancel it.

Now,

[tex]Ratio = \frac{r_1^2}{r_2^2}[/tex]

Since the ratio of the radii of circle Q to circle R = [tex]\frac{3}{4}[/tex]

We can also say that [tex]\frac{r_1}{r_2}=\frac{3}{4}[/tex]

Now we substitute the value of [tex]\frac{r_1}{r_2}[/tex] and get;

[tex]Ratio=(\frac{3}{4})^2=\frac{3^2}{4^2}=\frac{9}{16}[/tex]

Hence The ratio of the area of the sector for circle Q to the area of the sector for circle R is 9:16.