Question

In Exercises 20 and 21, determine the shaded area. When appropriate, use the key on your calculator and round your answer to the nearest hundredth.

20.

Answer 1

this just reeks of "test" for some reason

Answer 2

but it does say exercises soo ... thats a redeeming factor

Answer 3

no its a chapter review question for homework on college class

Answer 4

definantly a copy and paste tho :)

Answer 5

theses a picture or diagram that goes along with this i assume

Answer 6

this is the picture i need help with the question

Answer 7

the rectangle, by sheer equality i assume, is 8 by 8(3)

Answer 8

then subtract out the area of; well, 3 times a circle right?

Answer 9

this is just the quetion n picture im confused

Answer 10

do you see that the diameter of a circle in thepicture is 8?

and that 8 circles, side by side would be 8+8+8 for the top? as well as being 8 for the side?

Answer 11

ok

Answer 12

but im still not understanding very well

Answer 13

tell me where your confusion comes in at

Answer 14

the beginning where u said about the rectangle

Answer 15

..... do we need to be able to measure the sides of the rectangle in order to find its area?

Answer 16

im nott sure just want the question says and she wants all steps so i guess the more the better i get on it

Answer 17

your not sure .... how to determine the area of a rectangle.

Answer 18

no were just finding the shaded area

Answer 19

the shaded area is the whole area; minus the circles; so this is how we find it; by finding the whole, and taking out the parts that dont fit

Answer 20

oo ok

Answer 21

how do we find the area of ANY rectangle?

Answer 22

base times height?

Answer 23

thats correct; and we are given that the height is 8. Can you see a way to measure the base?

Answer 24

no

Answer 25

what is the diameter of each circle? the height of each circle that is ...

Answer 26

is the height of each circle equal to the height of the rectangle?

Answer 27

8

Answer 28

good; now a circle has the property that it is just as WIDE as it is TALL. so how WIDE is each circle of it is 8 tall?

Answer 29

8

Answer 30

correct. so let measure the width across the 3 circles, and that will be the measure of the base of the rectangle too right?

Answer 31

what is 8+8+8?

Answer 32

24

Answer 33

good, so do you agree that the rectangle has a base of 24 and a height of 8? if so, what is the area of the rectangle?

Answer 34

yes so the area of the rectangle 192??? not sure tho

Answer 35

the total area of the rectangle itself is: 192. Now we have to cut out the area of the circles. When we remove the area of the circles we will be left with the shaded parts. Do you see that?

Answer 36

ooo ok yea

Answer 37

so tell me, can you remember the formula for the area of a circle?

Answer 38

no i cant sry

Answer 39

thats ok, it takes practice to memorize these formulas

the area of a circle is measured as: pi r^2. where pi = 3.14 and "r" is the measure of half its height

Answer 40

ooo ok

Answer 41

what is half the height of a circle here?

Answer 42

4

Answer 43

and 4^2 = what?

Answer 44

4^2 mean 4 times 4

Answer 45

haha 16 drew blandk

Answer 46

:) 16 is correct.

So the area of 1 circle is: 16 pi, and we have 3 circles.

what is 16 times 3 equal?

Answer 47

48

Answer 48

good; so the total area that our circles cut out is: 48 pi

the shaded area left is then: 192 - 48pi

and this is where the calculator is needed since "pi" is not a number that can be accurately expressed.

Answer 49

ok

Answer 50

do you have a " \(\large\pi\) " key on your calculator?

Answer 51

no

Answer 52

well, it we approximate it now we run the risk of not getting the right answer that they are looking for.

Answer 53

lets use google: type in the search box:

192-48pi

then hit enter

Answer 54

http://www.google.com/search?gcx=w&sourceid=chrome&ie=UTF-8&q=192-49pi#sclient=psy-ab&hl=en&source=hp&q=192-48pi&pbx=1&oq=192-48pi&aq=f&aqi=&aql=1&gs_sm=e&gs_upl=2500l2606l0l2924l2l2l0l0l0l1l164l285l0.2l2l0&bav=on.2,or.r_gc.r_pw.&fp=48cf89d288d1a0a1&biw=1024&bih=677

Answer 55

-3.14

Answer 56

as you can see; we get something close to:

41.2035526

Answer 57

ooo i put it in wrong then

Answer 58

i got 188for some reason

Answer 59

click on the link i posted and it will show you the results

Answer 60

ok i got it now

Answer 61

good :)

41.2035526 to find out where the hundreths spot is in
100 our number, lets put the number 100 under
it like this.

We should be able to see from this that we need to round the spot at 41.20

Answer 62

so by going step by step so i can write this out

Answer 63

you can write it out if you want, but i got no idea how step by step it is.

Answer 64

ooo great ok thanks tho

Answer 65

41.203 this is what we should be concerned about

we need to know if that number on the end is bigger than 5? or less than 5.

is 3 bigger or less than 5?