Question

Please help.. I need to find the area of the shaded regions. could you please show me how you get the answer so i know how to

Answer 1

the area of a sector as in #26 is given by the formula (radian angle) times r^2 divided by 2.

You have 2 different "radiuses" in #26 so we just take the larger area with radius (R) and subtract the inner/smaller area with radius (r) from it and your left with the shaded area.

What are the Radiusesses involved in #26?

Answer 2

8 and 2

Answer 3

Diameter is 8; radius is half of that = 4; inner radius is 4.

Add 2 to that to get 6 for the outer radius. Does this make sense so far?

Answer 4

ya

Answer 5

good; the shaded area is actually the area of half of a circle. if that makes sense;

radian measurement is pi.

Outer area - inner area = shaded area

6^2pi/2 - 4^2pi/2 = ShA
36pi/2 - 16pi/2 = ShA
18pi - 8pi = ShA
10pi is the area of the shaded region of #26.

Answer 6

so 10*pi?

Answer 7

yes; 10*pi should be the area of the shaded portion in #26

Answer 8

so 31.4

Answer 9

if we are going to use 3.14 to equal pi; then you are correct.

Answer 10

okay

Answer 11

#27 seems to be missing a measurement. the inner shading is 1 cm radius; and the total outer is 7 cm radius; but what would the radius be for the middle section?

Answer 12

it doesnt say

Answer 13

I cant see a way to figure it out with those measurements alone. maybe im missing something... lets try #28

Answer 14

ok

Answer 15

that is the area of the isoTriangle - the area of the inner circle, just gotta recall how to find area of the isoTriangle..

Answer 16

the triangle should have an area of:

21 + 7sqrt(3)/2 and we subtract 36pi from it to get the shaded area.

Answer 17

are there any "multiple choice" answers to choose from?

Answer 18

no

Answer 19

k

Answer 20

27.06217782 - 36pi does not seem correct....gonna have to try again :)

Answer 21

its 27.73883783

Answer 22

108sqrt(3) - 36pi...

Answer 23

ok

Answer 24

I get 73.96 as long as I did it right :)

Answer 25

ok

Answer 26

and I get:

36pi - 18pi - 18
18pi -18

18(pi -1)

18(2.14) = 38.52

thats the best I can do fer ya :)

Answer 27

for what one?

Answer 28

#29...but I gotta recalculate..

it should end up being:

18(pi - 2)
18(1.14) = 20.52

I lost track of one of my sectors :)

Answer 29

6*6 = 36; thats a square area;

pi(36)/4 = 9pi = 1 sector
pi(36)/4 = 9pi = another sector

both sectors together are 18pi.

36pi - 18pi - 36
18pi - 36
18(pi - 2)
18(1.14) = 20.52

Answer 30

thats all I can help you with; hope it helps :)

Answer 31

okay thank you