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 2 years ago
Megan bought an outdoor wall light fixture. The fixture has semicircular ends at the top and bottom as shown. The side of the fixture that faces the wall is open.
What is the exterior surface area of the light fixture?
Answer
78π in2
84π in2
108π in2
120π in2
 2 years ago
Megan bought an outdoor wall light fixture. The fixture has semicircular ends at the top and bottom as shown. The side of the fixture that faces the wall is open. What is the exterior surface area of the light fixture? Answer 78π in2 84π in2 108π in2 120π in2

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apoorvk
 2 years ago
Best ResponseYou've already chosen the best response.2Just need to find the surface area of each semicircle part, and add 'em up. Or rather, two same semicircles make a circle! so, find out the are of a circle which has a diameter of '12in'. Then, add the area of the rectangular part > 12x14  right? What do you think now?

cbrusoe
 2 years ago
Best ResponseYou've already chosen the best response.1i did something way off ... but im not sure what i found the formula for a cylinder and i plugged in my numbers and calculated it and got 753.6 ....

apoorvk
 2 years ago
Best ResponseYou've already chosen the best response.2it's not a cylinder! its like a lampshade kinda thing  two semicircular shades, and a rectangular background.

cbrusoe
 2 years ago
Best ResponseYou've already chosen the best response.1i know but if we added the other half... aha ... ok so what equation do i use?

apoorvk
 2 years ago
Best ResponseYou've already chosen the best response.2find the area of the rectangular part, then are of each semicircular shade and add em up!

cbrusoe
 2 years ago
Best ResponseYou've already chosen the best response.1ok the area of the rectangular part is 168 now i need to find the area of each semicircular shade ... how do i do that?

cbrusoe
 2 years ago
Best ResponseYou've already chosen the best response.1sorry ive been working since 6 this morning nonstop... i dont think im trying as hard ... cuz this probably something i should get

apoorvk
 2 years ago
Best ResponseYou've already chosen the best response.2its okay  i am woozy too :P. area of semicircle = (1/2) area of circle plus you could think this way  two same semicircles make a circle, so just find the area of the the equivalent circle..

cbrusoe
 2 years ago
Best ResponseYou've already chosen the best response.1ok well i know the formula for the area of a circle is pi*r2 so since the diamiter is 12 the radius would be 6 plug that in and i got 113.04

cbrusoe
 2 years ago
Best ResponseYou've already chosen the best response.1uugh but adding those up gives me to big of a number hmmm

cbrusoe
 2 years ago
Best ResponseYou've already chosen the best response.1well it adds up to 281 which isnt one of my options

cbrusoe
 2 years ago
Best ResponseYou've already chosen the best response.178π in2 84π in2 108π in2 120π in2

apoorvk
 2 years ago
Best ResponseYou've already chosen the best response.2i am sorry, it's too late here, and i am too woozy  i misunderstood the whole thing  it must be a cylinder itself  i am really sure this time though. @Diyadiya will help you out. Thanks :) and apologies for misguiding  didn't mean it.

cbrusoe
 2 years ago
Best ResponseYou've already chosen the best response.1it's ok thanks for the help =) and ok =)

apoorvk
 2 years ago
Best ResponseYou've already chosen the best response.2yeah would be the last one  just help her understand.

Diyadiya
 2 years ago
Best ResponseYou've already chosen the best response.3First find the area of two semicircles area of semicircle = (pi * r^2)/2 =pi*(6)^2/2 =18pi 2 semicircles =18pi+18pi=36pi

Diyadiya
 2 years ago
Best ResponseYou've already chosen the best response.3did you understand til this ?

cbrusoe
 2 years ago
Best ResponseYou've already chosen the best response.1yeahh when we go to the semi circle stuff i think is when i started to get confused

Diyadiya
 2 years ago
Best ResponseYou've already chosen the best response.3Now its half of a cylinder

Diyadiya
 2 years ago
Best ResponseYou've already chosen the best response.3and i guess the rectangular part is open

Diyadiya
 2 years ago
Best ResponseYou've already chosen the best response.3You just have to find the lateral surface area of half of cylinder ( 2*pi*r*h) half cylinder so lateral surface area = 2*pi*r*h/2 =Pi*r*h can you do it?

cbrusoe
 2 years ago
Best ResponseYou've already chosen the best response.1yeahh i can do it thankyou =)

Diyadiya
 2 years ago
Best ResponseYou've already chosen the best response.3can you tell me the lateral surface area of it ?

cbrusoe
 2 years ago
Best ResponseYou've already chosen the best response.1ok when i calculate 2*pi*r*h i got 263.76

Diyadiya
 2 years ago
Best ResponseYou've already chosen the best response.3don't take the value of pi .. just keep pi like that since your answer contains pi

Diyadiya
 2 years ago
Best ResponseYou've already chosen the best response.3so what will be the lateral surface area ?

cbrusoe
 2 years ago
Best ResponseYou've already chosen the best response.1ok so 2*r*h and my diamiter is 12 so radius would be 6 and height is 14 so 2*6*14 = 168pi?

Diyadiya
 2 years ago
Best ResponseYou've already chosen the best response.3Yes this is the lateral surface area of a cylinder but we have only half of a cylinder so divide it by 2

Diyadiya
 2 years ago
Best ResponseYou've already chosen the best response.3and add the area of 2 semicircles

cbrusoe
 2 years ago
Best ResponseYou've already chosen the best response.1ok so 84 plus the are of 2 semicircles

cbrusoe
 2 years ago
Best ResponseYou've already chosen the best response.1i may have calcuulated that last part wrong
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