Question

Help please!

Answer 1

What is the best approximation for the perimeter of a semicircle with a diameter of 12 cm?

Use 3.14 to approximate pi.

18.84 cm
30.84 cm
61.68 cm
75.36 cm

Answer 2

@dude

Answer 3

To make this less complicated lets find the circumference of a regular circle and then divide it by 2 (Since a semicircle is just half a circle)

Answer 4

\(C=\pi d\)

Answer 5

Huh?

Answer 6

could someone help me?

Answer 7

i'll help you?

Answer 8

What you need help with?

Answer 9

Use a net to find the surface area of the right triangular prism shown below:

Three rectangles next to each other with a width of 7 feet. The first and second rectangles length are unknown, and the last is 10 feet long. There are two right triangles above and below the last rectangle. One is labeled with a base of 6 feet and a height of 8 feet.

198 square feet
216 square feet
270 square feet
280 square feet

Answer 10

that
is what i need help with

Answer 11

Elizabeth do not post your questions on someone elses post @Ultrilliam

Answer 12

the answer is to yours is?

Answer 13

30.84

Answer 14

Do not give out incorrect answers or any direct answer for that matter :|

Answer 15

it not incorrect

Answer 16

Please don't post questions on someone elses post, use the "ask a question" box to ask your question

Answer 17

ok

Answer 18

Okay so what were you saying dude?

Answer 19

So we are trying to find the perimeter of a semi circle, because there is no direct equation to find it we can solve for the perimeter of a regular circle first and then divide it by 2

Answer 20

How do we do that?

Answer 21

We can use the equation
\(C=\pi d\)
C being circumference AKA its perimeter
d being the diameter

Answer 22

And the other symbol being pie

Answer 23

Yes and in your case it should be 3.14

Answer 24

So
\(C=3.14\cdot 12\)

Answer 25

37.68

Answer 26

Right so we know the perimeter of a full circle, to find the perimeter of a semicircle we divide what we have by 2

(Since a semicircle is just half a circle)

Answer 27

18.84

Answer 28

And that is your answer

Answer 29

18.84 is wrong

Answer 30

No it's not

Answer 31

i did this test it is wrong

Answer 32

but whatever bye

Answer 33

Is it okay if I post another question here instead of starting another question?

Answer 34

@Elizabeth How did you get 30.84?

Answer 35

i studies and the answer was 30.84 on my test i got it right but "i'm not supposed to give direct answers"

Answer 36

I'm just going to keep it as 18.84

Answer 37

I thought you'd have work to support it but ok

Answer 38

Ah I see my mistake
I only found the perimeter of the outer part of the circle

I found the blue arrow
I forgot to include the measure of the red area (diameter)

18.84+12=30.84

Answer 39

@Elizabeth Thank you for telling me about my mistake I apologize for misjudging the answer

Answer 40

It is better explained here https://www.youtube.com/watch?v=Tk39_aQWn1g
If you can access YouTube