## ErinWeeks 3 years ago Find the surface area of the figure to the nearest whole number. PLEASE HELPPPP

1. ErinWeeks

A. 310 ft2 B. 158 ft2 C. 135 ft2 D. 74 ft2 I thought it was C but it was wrong -_-

2. anonymous

the back side in the image is very confusing :/

3. ErinWeeks

its 2.5 and 3.3

4. anonymous

hint: split it into two objects. find the surface area of the top triangle pyramid and add it to the surface area of the square prism

5. ErinWeeks

im still confused

6. anonymous

but you understand what I said?

7. ErinWeeks

i dont really -_-

8. anonymous

k wait, let me work through the whole thing first then I'll explain it to you.

9. ErinWeeks

okay thank you

10. anonymous

|dw:1357770316535:dw| see I split the two? this is what I meant and excuse my drawing. Note: we do not need to find the bottom base of the pyramid and top of the square prism, as it is not accounted towards the total surface area. (It's the part where they are glued together if you may).

11. anonymous

well i can to see 2 solids... the piramid and the cube.. so the piramid area is $\frac{ 1 }{ 2 }* perimetre*face length$. in your piramid $\frac{ 1 }{ 2 } \times 18\times 3.3$ and the cube surface

12. ErinWeeks

for the second formula i got 29.7 ... i dont know how to do the 1st one

13. anonymous

yes 29.7 is right for the top(pyramid).

14. ErinWeeks

okay now can you explain how to do the bottom

15. anonymous

for the bottom(square prism) it is even easier. 2(4.5 x 6 + 4.5 x 6) + (4.5 x 4.5)

16. anonymous

this is because the top of the square prism(where it needs to be used to be stuck against the bottom part of the pyramid) is not accounted for.

17. ErinWeeks

i got 74.25 now what ??

18. anonymous

19. anonymous

20. ErinWeeks

i got 103.95 but thats not a choice

21. anonymous

your 74.25 you got is wrong, try again.

22. anonymous

it should be 128.25

23. anonymous

no, it is $4(4.5*6)+ 2(4.5*4.5)$

24. ErinWeeks

with @ankolix formula i got 142.5

25. anonymous

@ankolix I don't think you understand the concept that you only need 4.5 x 4.5 once not twice.

26. ErinWeeks

@JayDS my answer and your answer are both not an option

27. anonymous

yeah.. ivemistake

28. anonymous

please tell me the options.

29. ErinWeeks

A. 310 ft2 B. 158 ft2 C. 135 ft2 D. 74 ft2

30. anonymous

and you made a calculation error before, so please be careful when entering it in the calculator.

31. anonymous

is 4(4.5*6)+(4.5*4.5)+29.7=157.95.. option B

32. anonymous

yep, option B.

33. anonymous

using my calculation you will get 157.95. and why is it not exact? because probably when they calculated they used more decimal places which resulted them to get a more accurate answer but we have been only given that, so we just those figures in the picture.

34. anonymous

medal for gratitude ;)

35. ErinWeeks

okay thank you so muchh..

36. anonymous

@ankolix, I would like to say you deserve the medal for trying but you have copied off me but good job.