Question

A circular bicycle reflector has a diameter of 5 cm.

What is the approximate area of the reflector? Use 3.14 to approximate pi and round your answer to the nearest hundredth.

PLEASE HELP

Answer 1

@Babynini

Answer 2

i will give medal and fan

Answer 3

@Babynini

Answer 4

is it 78.5

Answer 5

@jeweaver6895

Answer 6

help help help help help @Babynini and @jeweaver6895 help help help help help

Answer 7

u r in now

Answer 8

Ok, i'm here! give me a moment :)

Answer 9

hahahaha, XD, i understand

Answer 10

Ok, so again, the equation is: \[r^2 \times \pi = area of circle\]
What they've given you is the diameter (5)
The radius is half of the diameter which = ?

Answer 11

i said 5(2)x3.14

Answer 12

the 2 is small on the right top corner of the 5

Answer 13

Make sure you use the radius and not the diameter in the equation!

Answer 14

oh, so what shall i do

Answer 15

oh, so radius, so is it 2.5(2) x 3.14

Answer 16

Perfect :)

Answer 17

that would be 19.625

Answer 18

Good job!

Answer 19

do u mind helping me with one more, i will post the questio here so u do not have to get lost around openstudy

Answer 20

Sure. Haha thanks xD

Answer 21

Figure GHJK is equivalent to a rectangle with a semicircle removed from both its top side and its bottom side.

What is the area of figure GHJK?




A.
( 192 – 288 ) ft2

B.
( 192 – 144 ) ft2

C.
( 192 – 72 ) ft2

D.
( 192 – 36 ) ft2

Answer 22

http://static.k12.com/calms_media/media/1571000_1571500/1571380/1/a5d8fffdb08094c6a8eaa9a1d614529ac696221a/MS_IMB-1401212-1110908.jpg

Answer 23

the question diamond things are just minus symbols

Answer 24

Ok.

Answer 25

and after 36 and 72 and 144 and 288 are pi symbols as well

Answer 26

sorry it seems all disombobulated

Answer 27

Ok, the diameter of the half circles are 12, which means the radius = ?

Answer 28

6

Answer 29

Perfect, so go ahead and plug that into our equation, which would make the area of the circle =

Answer 30

113.04??

Answer 31

ang on, that is wrong

Answer 32

h

Answer 33

No no that's correct :)

Answer 34

113.04 is correct that is the answer

Answer 35

what grade r u in

Answer 36

i am in 7th

Answer 37

Ok, since two halves equal a whole (and you have to semi-circles) you don't have to worry about splitting that number in half or anything. So you've got an area for a whole circle of 113.04

Answer 38

but which is the answer choice

Answer 39

ok

Answer 40

Go ahead and find the area of the square as if it were a normal square

Answer 41

16= 8, so

Answer 42

that would be 200.96

Answer 43

right!?!?!

Answer 44

Not quite.

Answer 45

To find the area of a square just times both sides! So the equation for the area of the square would be: 16 x 12 =

Answer 46

192

Answer 47

yep!

Answer 48

now what

Answer 49

Now, it's got two circles cut out of it, so you're going to MINUS the area of your circle from the area of the square. Does that make sense?

Answer 50

Do you understand why you're going to do that?

Answer 51

113.04 - 192?

Answer 52

Nope, because you're finding the area of the shaded portion. So the area of the rectangle - area of the square =

Answer 53

192 -113.04 =

Answer 54

78.96

Answer 55

oops sorry, Idk why that sent!

Answer 56

That's exactly right, done like a boss :D

Answer 57

what grade r u in

Answer 58

11th

Answer 59

cool

Answer 60

c is for me

Answer 61

i will tell u what i get

Answer 62

Alright :) Good luck! Let me know if you need any help in the future.

Answer 63

i got 70%

Answer 64

:(

Answer 65

Is this an online test?

Answer 66

the answer is really D