A circle has a sector with area 27\pi27π27, pi and central angle of \purple{120^\circ}120 ∘ start color #9d38bd, 120, degrees, end color #9d38bd. What is the area of the circle?

The radius of the circle is 9 units.

Step-by-step explanation:

To calculate the area of the circle we need to find it's radius, since we have the area of the sector and it's angle, therefore we can calculate the radius by using the following formula:

sector area = (central angle)*pi*r²/360

27pi = 120*pi*r²/360

27pi = pi*r²/3

27 = r²/3

r² = 81

r = sqrt(81) = 9

The radius of the circle is 9 units.

a 4/6 = 9/12   not proportional

step-by-step explanation:

to find which are not proportional, we can use cross products

if it is true, they are proportional.   if it is not true, they are not proportional.

a 4/6 = 9/12

4* 12 = 6*9

48 = 54

not this is not proportional  

b 2/3 = 12/18  

2* 18 = 3 * 12

36 = 36

this is proportional

c 5/4 = 10/8  

5*8 = 4*10

40 = 40

this is proportional

d 7/5 = 35/25

7*25 = 5 * 35

175 = 175

is proportional