## gabbyalicorn one year ago The prism has a surface area of 202 ft2. What would the surface area of the prism be if each dimension were tripled?

1. gabbyalicorn

2. Michele_Laino

the new dimensions are: 5*3=... 9*3=... 4*3=...

3. gabbyalicorn

15 27 and 12

4. Michele_Laino

correct!

5. gabbyalicorn

then x by them?

6. gabbyalicorn

which us 4860

7. Michele_Laino

8. gabbyalicorn

kk

9. Michele_Laino

your problem asks for the area of the total surface of the prism. Now the area of the total surface of your prism is given by the subsequent computation: A=2*(15*27+ 15*12+27*12)=...

10. gabbyalicorn

i got 121608

11. gabbyalicorn

is that correct?

12. Michele_Laino

here more steps: $\Large \begin{gathered} A = 2 \times \left( {15 \times 27 + 15 \times 12 + 27 \times 12} \right) = \hfill \\ \hfill \\ = 2 \times \left( {405 + 180 + 324} \right) = ... \hfill \\ \end{gathered}$

13. gabbyalicorn

1314

14. Michele_Laino

I got a different result

15. gabbyalicorn

wait do we add the two together?

16. Michele_Laino

yes!

17. gabbyalicorn

i got 122922

18. Michele_Laino

you have to compute this: 405+180+324=... $\large \begin{gathered} A = 2 \times \left( {15 \times 27 + 15 \times 12 + 27 \times 12} \right) = \hfill \\ \hfill \\ = 2 \times \left( {405 + 180 + 324} \right) = \hfill \\ \hfill \\ = 2 \times 909 = ... \hfill \\ \end{gathered}$

19. gabbyalicorn

1818 plus 122922 = 124740

20. Michele_Laino

no, it is: A= 1818 feet^2 only

21. gabbyalicorn

-3- hm?

22. gabbyalicorn

I didnt get that, sorry. :/

23. Michele_Laino

the new area of the total surface is, namely your answer, is: $\Large \begin{gathered} A = 2 \times \left( {15 \times 27 + 15 \times 12 + 27 \times 12} \right) = \hfill \\ \hfill \\ = 2 \times \left( {405 + 180 + 324} \right) = \hfill \\ \hfill \\ = 2 \times 909 = 1818fee{t^2} \hfill \\ \end{gathered}$

24. gabbyalicorn

oh :l

25. gabbyalicorn

i see now...

26. Michele_Laino

since we have to sum the area of all of the six sides of your prism

27. gabbyalicorn

so 10908? 1818 x 6

28. Michele_Laino

29. gabbyalicorn

oh kk. Thank you!!! ^u^

30. Michele_Laino

:)

31. jim_thompson5910

Old Surface Area = 202 ft^2 New Surface Area = 1818 ft^2 Notice we have this ratio: (new area)/(old area) = 1818/202 = 9 and how 3^2 = 9. This is no coincidence. The old surface area is multiplied by 3^2 = 9 to get the new surface area. If you asked "What would the surface area of the prism be if each dimension were quadrupled?", then you would multiply the old surface area by 4^2 = 16 to get the new surface area