Question

Please Please Help!!!!!
1.What is the surface area of the composite figure?

Answer 1

hint (see attached image)

Answer 2

the red regions are NOT counted (since they the parts that are covered by the other solids)

Answer 3

surface area of a rectangular prism is SA=2lw plus 2lh plus 2wh

Answer 4

correct, or

SA = 2*(LW + LH + WH)

Answer 5

SA=2(6*3) plus 2(6*3) plus 2(3*3)
SA=2(18) plus 2(18) plus 2(9)
SA=36 plus 36 plus 18=90

Answer 6

so what you basically do is find the surface area of each block (after you break them up)

then you subtract off the red regions

Answer 7

that is for the one one the left

Answer 8

confused

Answer 9

you can just break them into two rectangular prisms right?

Answer 10

90 is the surface area of the smaller prism on the left, yep

Answer 11

yes you can break them up

Answer 12

12cm would be for what?

Answer 13

ignore that bit

Answer 14

it's actually 15 cm long (not 12)

Answer 15

we'll deal with the red regions later

Answer 16

the one on the bottom

Answer 17

I know, don't worry about the 12

Answer 18

SA=2(15*30) plus 2(15*3) plus 2(3*3)
SA=2(450) plus 2(45) plus 2(9)
SA=900 plus 90 plus 18
SA=1,008

Answer 19

wrong

Answer 20

way too high

Answer 21

yeah

Answer 22

it's not 30, it's 3

Answer 23

change the 30 to 3 and that will fix things

Answer 24

90 plus 90 plus 18=198
198 plus 90=288

Answer 25

now subtract off the red areas

Answer 26

these are the answers

two hundred sixteen square centimeters

two hundred thirty-four square centimeters

two hundred seventy square centimeters

three hundred twenty-four square centimeters

Answer 27

each red area is 3x3, so 3*3 = 9 square units

288 - 9 - 9 = 270

Answer 28

a bit annoying how all the answers are spelled out like that, but it's choice C

Answer 29

okay

Answer 30

i tried

Answer 31

well just keep practicing and you'll get better

Answer 32

thx

Answer 33

np