## Faman39 Group Title You are making poster board boundary markers in the shape of square pyramids for a relay race. If you are including a 12 -inch square as the bottom and you want the slant height to be 14 inches, how much poster board do you need? 252 in2 420 in2 480 in2 532 in2 2 years ago 2 years ago

1. Faman39

@UnkleRhaukus can you able to help me ?

2. UnkleRhaukus

|dw:1352387741795:dw|

3. Faman39

I still cant get this, can you able go in bit detail ?

4. UnkleRhaukus

can you see how i flattened all the surfaces a plane?

5. Faman39

Yes

6. UnkleRhaukus

you have a square , and four big triangles,

7. Faman39

ok

8. UnkleRhaukus

the area of a square is the side length squared the area of a triangle is half of the base times the height

9. Faman39

Are we gonna....multiply 14 and 12?

10. Faman39

i am sorry i am totally talking wrong

11. UnkleRhaukus

yes the base of the triangles is 12 and they have a height of 14 , the area of each tringle is half these multiplied together

12. Faman39

but i got 168 ? :(

13. UnkleRhaukus

how?

14. Faman39

I do not know, probably i m doing wrong i know :(

15. Faman39

that must be for it

16. UnkleRhaukus

what did you get for the area of the square? and what did you get fo the area of each triangle ?

17. Faman39

i multiply 14 with 12 :(

18. UnkleRhaukus

the area of a triangle is HALF of the base times the height

19. Faman39

so half * 14 * 12

20. UnkleRhaukus

what do you get?

21. Faman39

84 :(

22. UnkleRhaukus

right so , one triangle is 84 in^2 what is the area of the square

23. Faman39

12?

24. UnkleRhaukus

the area of a square is the side length squared $12^2=$

25. Faman39

14 ?

26. Faman39

27. UnkleRhaukus

$12^2=12\times12=$

28. Faman39

144

29. UnkleRhaukus

right

30. UnkleRhaukus

the total area is made up of 4 triangles and one square ,

31. Faman39

So we divide 4 with 144 ?

32. UnkleRhaukus

add the area of the square to four times the area of the triangle

33. Faman39

Still not getting any correct point

34. Faman39

i am so sorry, i m horrible that i m getting wrong answer

35. Faman39

144 * 12 * 4 ?

36. UnkleRhaukus

$A_{\text{square}}=12 [\text{in}]\times12 [\text{in}]=144 [\text{in}]^2$ $A_{\text{triangle}}=\frac{14 [\text{in}]\times12 [\text{in}]}2=84 [\text{in}]^2$ $SA_{\text{square pyramid}}=A_{\text{square}}\quad+\quad4\times A_{\text{triangle}}$

37. Faman39

Thank you so so much @UnkleRhaukus, your so awesome and genius!!!!!

38. Faman39

thanks alot! And i m sorry for troubling :(

39. Faman39

i know, i m totally pain, cuz i barely understand thing

40. UnkleRhaukus

i hope it makes some sense now, can you tell me how much poster board do you need?

41. Faman39

480 in2

42. UnkleRhaukus

$\color\red\checkmark$

43. Faman39

Thank you so much @UnkleRhaukus !!! your too great!!!!!!