1. anonymous

For these 3 pictures.. i need to find the surface area

2. anonymous

the first one is composed of 2 triangles: 4x5 + 4x5 = 40m 3 rectangles: 4x14 + 5x14 + $14\times \sqrt{4^{2} + 5^{2}}$ and you add all of them up

3. anonymous

so the first one would be 89.64?

Area of triangle is BH/2, in this figure that equals (4 x 5)/2=20/2=10 sq M, but their are two so the surface area of the triangular portion would be 20 sq meter.

5. anonymous

for the first one i got 2(20)+Ph.. i need to find out what the perimeter is

The suface of the sides are as indicated by tacolover. 5x14= 70 sq M for one side. 4x14=56 sqM for another side and 14 x sq rt(16+25) $\sqrt{41}\times14$

7. anonymous

im totally lost... the formula i have to use is 2B+Ph

9. anonymous

so that would be for the first one?

That will work too

yes as long as you remember that the B is a triangle and their are two of them.

P is perimeter and you must user all three sides.

You want to look at the next figure?

14. anonymous

yeah.. so far for the next one i got 2(28)+Ph

It is a cylinder or like a can. Too find the total surface area you calculate the area of the ends which are circles (don't forget their are two of them. Then the body is actually a rectangle which has one side equal to the circumference of the circle times the height.

Do you agree?

17. anonymous

yeah.. sorry for some reason i put up the wrong picture.. but i need help with that one to

18. anonymous

so id use 2*pi*r^2+2*pi*r*h

Do you know how calculate the area of circle whose diameter is 8cm or radius would be 1/2 of that or 4 cm.??

The area of the ends would be as you have but it would be like 2(2*pi*r^2). Then the can (not the ends) would be h*C 8*piD=8*pi*8

I am sorry I got the area wrong for the ends. The formula is pi*r^2 so the ends would be 2(pi*r^2) that is for both ends

22. anonymous

so for r would it be half the diameter (8).. so 2(3.14*4^2)

Yes that gives you the area for the ends of the cylinder. both

24. anonymous

so 100.48

Let me check yes for the ends. Now this must be added to the surface area of the body of the can pi*D*h

26. anonymous

so 3.14*8*12=301.44

28. anonymous

Yes that would give you the total surface area of the can, I forgot that the heigth was 12 and put 8 but you caught it!

and that is in sq cm

31. anonymous

okay

Do you need any help on the 3rd figure.

33. anonymous

no but will you check this one for me

34. anonymous

i got 326.25m^2

Does it have a bottom and a top? It is hard to tell from the drawing!

36. anonymous

yea

I used calculator and got 326.73, so I would say you used the correct procedure and don't forget what the units are.......sq M

38. anonymous

ok thank you

39. anonymous

can you also check this one.. i got 254.34 ft^2