What is the surface area of the composite figure?

64 square centimeters

108 square centimeters

124 square centimeters

136 square centimeters

Question

What is the surface area of the composite figure? 


64 square centimeters 

108 square centimeters

124 square centimeters

136 square centimeters

anonymous · Answer

attachment

anonymous · Answer

plz help!!!

geerky42 · Answer

attachment

geerky42 · Answer

Find area of each rectangle on this figure, then add them all together.

anonymous · Answer

k hold on a sec

anonymous · Answer

the top one is 104 and the bottom one is 40

104 + 40 is 144

am i right?

anonymous · Answer

so far

anonymous · Answer

gerky?

geerky42 · Answer

No, let's color this figure, to make it easier:

Give me a min to color it

anonymous · Answer

okay..

geerky42 · Answer

It's ugly, but we don't need it to be perfect. 

Anyway, you can see that area has "color"

Some of them doesn't appear in visible.

So tell me how many blue areas do this figure have?

anonymous · Answer

3

geerky42 · Answer

We can see 3, but there is more (see red arrow)

anonymous · Answer

i swear the surface area of the two figures added together is 144

anonymous · Answer

okay

geerky42 · Answer

So there is 5 blue area.

So $5(2\times2)$

We still have more area. How many green areas?

geerky42 · Answer

144 is not right

anonymous · Answer

5(2x2) = 20

and 2

geerky42 · Answer

Sorry, let forgot about that. 

You said you got surface area of two rectangle prisms total of 144, right? There is part that you over count we need to subtract from.

anonymous · Answer

is the answer 136?

i think i caught on to what you were doing and all

geerky42 · Answer

Yeah answer is 136. you can split it into two rectangle prisms, then subtract area we count whereas we shouldn't 

For example, you got 144. but we counted red area twice, so we subtract 144 by 2(2*2)  which is 8

So 144-8 = 136

geerky42 · Answer

I though color approach is too long, lol

anonymous · Answer

ah thanks so much

imma try this next composite figure, and can you tell me if my answer is right or wrong?

and that way helped me a lot better then what I learned in my lesson and all :)

geerky42 · Answer

ok sure

anonymous · Answer

okay hold on a sec

anonymous · Answer

wait nvm it is volume

all i gotta do is add the volume of the two figures together

thanks for helping

geerky42 · Answer

I still can check, so you sure?

geerky42 · Answer

ok well, welcome.

anonymous · Answer

sure i am finding the volume i got 135