## ErinWeeks 2 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. ankolix

the back side in the image is very confusing :/

3. ErinWeeks

its 2.5 and 3.3

4. JayDS

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. JayDS

but you understand what I said?

7. ErinWeeks

i dont really -_-

8. JayDS

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

9. ErinWeeks

okay thank you

10. JayDS

|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. ankolix

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. JayDS

yes 29.7 is right for the top(pyramid).

14. ErinWeeks

okay now can you explain how to do the bottom

15. JayDS

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

16. JayDS

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. JayDS

19. JayDS

20. ErinWeeks

i got 103.95 but thats not a choice

21. JayDS

your 74.25 you got is wrong, try again.

22. JayDS

it should be 128.25

23. ankolix

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

24. ErinWeeks

with @ankolix formula i got 142.5

25. JayDS

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

26. ErinWeeks

27. ankolix

yeah.. ivemistake

28. JayDS

29. ErinWeeks

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

30. JayDS

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

31. ankolix

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

32. JayDS

yep, option B.

33. JayDS

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. ankolix

medal for gratitude ;)

35. ErinWeeks

okay thank you so muchh..

36. JayDS

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