surface area circle

[fallow snow]

still need help?

@tame briar

since the sphere is a quarter, the curved area can be worked out using the surface area formula

so u basically quarter the 4pi r^2
which gives u just pi r^2

the flat area can be worked out using the area of a circle which is pi r^2

so the total surface area is just 3 pi r^2 if u add all this up

finally to get the radius, u use whats given... so 576=4/3 pi r^2
rearrange this ro get pi on its own.... so (576 x 3)/4 = pi r^2
432= pi r^2
432/pi=r^2
sqr rt (432/pi) = r

yeah

[fallow snow]

and then plug that in to this

what was ur final ans?

nah thats not 3.s.f

oh wait nvm ur right

is that correct?

mb mb lemme check this out rq

yeah isee what i did

its meant to plug into 2 pi r ^2

[fallow snow]

since the flat area as a whole is two semi circles which make up one full circle

did it work?

yeah sorry bout the wrong answer... one sec just @ a mentor rq

<@&791435371564892232>

wait

try 864 rq pls

ur meant to carry on the entire value, rather than a rounded figure, since it causes errors carried forward

yeah u always carry the full value forward lol

[fallow snow]

if it's not this, then im sorry for wasting your time 😢 idk where else it could of went wrong. Oh yeah I also got the rearranging wrong ,since the power of 3 looked like 2. I'm so sorry 😔

oh damn

[compact remnant]

is it 905 cm² ?

[scenic lodge]

rearrange equation find radius

575pi = 4/3pir^3

r^3 = 432

r = 7.559526299

find SA

4 x 7.5595^2 x pi / 4

and then add on area of the two semi circles, so pi x 7.5595^2

[compact remnant]

i dont think thats right

idk what kinda method that is

[compact remnant]

the volume is 576 pi not 575

also since its a quarter-sphere the formula for volume is 1/3 pi r^2 , not 4/3

right method/process but u missed some steps

[scenic lodge]

oh

oops

[scenic lodge]

What

Its not a hemisphere bro

I did it jsut as i woke up

so i probably made some dumb mistakes

[compact remnant]

quarter-sphere*

[compact remnant]

LOL

dw

[scenic lodge]

Here ok

r^3= 1728

cuz u do 576pi divided by 1/3pi

r = 12

[compact remnant]

yes

[scenic lodge]

And then u find the surface area

4 xpi x 12^2 / 4

the area of the 2 semicircles

pi x 12^2

[compact remnant]

its 2 pi r^2

r * pi * 12^2

[scenic lodge]

what

but its 2 semicircles

so in total its one circle

[scenic lodge]

yeah

[compact remnant]

so

the two semicircles add to make 1 circle

[scenic lodge]

2 semi circles

[compact remnant]

but also the back is the surface area

its 1/4

[scenic lodge]

I worked out the back

[compact remnant]

so u do 1/4 * 4 pi r ^2

[scenic lodge]

here

[compact remnant]

which is also pi r^2

[scenic lodge]

yh

[compact remnant]

yeah so u add them

for total

[scenic lodge]

mhm

[compact remnant]

pi r^2 + pi r^2

so 2 pi r^2

[scenic lodge]

ah ye