## waheguru Group Title need some help im getting 311 2 years ago 2 years ago

1. GT Group Title

ok

2. jhonyy9 Group Title

???

3. karatechopper Group Title

311?

4. waheguru Group Title

im posting the question sorry

5. waheguru Group Title

6. waheguru Group Title

here we are

7. meverett04 Group Title

Do you have the formula for the surface area of a cylinder?

8. waheguru Group Title

2pirsq plus 2pirh

9. GT Group Title

Surface area of fully cylinder = circumference * length. Here, you have half of it. So, 1/2*circumference*length = 1/2 * pi * 6 * 30 = 90 * pi

10. jhonyy9 Group Title

a.

11. GT Group Title

waheguru - that is when including bottom and top circles. In this case, the roof has no such thing. So, you just need 1/2 circumference * length.

12. asnaseer Group Title

@GT is right

13. waheguru Group Title

oh so i included the bottom???

14. GT Group Title

Yeah. Don't.

15. waheguru Group Title

k so this is what i did 2 x pi x 3^2 + 2 x pi x 3 x 30 and divide by 2

16. duha2011 Group Title

hi

17. GT Group Title

Remove 3*pi*r^2 and the rest is good.

18. waheguru Group Title

y

19. jhonyy9 Group Title

a. is right sure

20. GT Group Title

Because the roof does not have a base and top (according to the problem description).

21. asnaseer Group Title

the question is asking for the area of the roofs curved surface - that does not include the two ends of the greenhouse

22. waheguru Group Title

so just the lateral

23. GT Group Title

yes.

24. waheguru Group Title

thx brozz

25. asnaseer Group Title

the curved surface of a cylinder has a surface area of $$2\pi rh$$. in this case you have half a cylinder, so the surface area becomes $$\pi rh$$

26. duha2011 Group Title

HI GUYS

27. waheguru Group Title

just practising for grade 9 EQAO

28. asnaseer Group Title

what is EQAO?

29. waheguru Group Title

evil questions attacking ontario lol im kidding its like an exam for grade 9 students

30. asnaseer Group Title

lol! :-D - good luck with them...

31. waheguru Group Title

thx

32. jhonyy9 Group Title

is half perimeter of base multiply lenght=surface area

33. jhonyy9 Group Title

this very easy

34. asnaseer Group Title

@jhonyy9 - things are always easy when you know how to do them - try and recall the days when you were also at the lower end of the learning curve :-)

35. asnaseer Group Title

like we ALL were

36. jhonyy9 Group Title

yes right but this is the same like a rectangle curved on the base