Question

If two sectors have an area of 12π square units, and one sector is from a circle with radius 6 units, while the other is from a circle with a radius of 4 units, how do the central angles for these sectors compare?

Answer 1

Answer:

Thus, the ratio of the central angles is 4 : 9.

Step-by-step explanation:

Area, A = 12 π square units

radius, R = 6 units

radius, r = 4 units

Area of sector is given by

$A=\frac{\theta }{360}\times \pi r^{2}$

For first sector

$12\pi=\frac{\theta }{360}\times \pi \times 6^{2}\\\\\theta = 120^{o}$

For second sector

$12\pi=\frac{\theta' }{360}\times \pi \times 4^{2}\\\\\theta' = 270^{o}$

So, the ratio is

$\frac{\theta}{\theta'}=\frac{120}{270} =4 : 9$

Answer 2

Answer:

4 : 9

Step-by-step explanation:

Given:

Two sectors, each has an area of 12pi, but with radii r1=6 and r2=4 units.

Find ratio of central angles.

Solution:

Let A = central angle

Area of a sector = pi r^2 (A/360)

Since both sectors have the same area,

pi r1^2 (A1/360) = pi r2^2 (A2/360)

simplifying

A1 r1^2 = A2 r2^2

Therefore

A1 : A2  = r2^2 : r1^2 = 4^2 : 6^2 = 4 : 9