How do you find the surface area for this shape?

Step-by-step explanation:

Add up the surface areas of each of the 6 faces.

There are two top/bottom faces with the same area, two left/right faces with the same area, and two front/back faces with the same area. So you only need to figure the areas for 3 faces, then multiply that sum by 2. Of course the area of each rectangle is the product of its length and width. For length, width, and height dimensions L, W, and H, the total area is ...

A = 2(LW +WH +LH)

  = 2(LW +H(L+W)) . . . . . I like this form because there's one less multiplication

  = 2(5·4 + 1.5(5+4)) = 2(20 +13.5)

A = 67 . . . units²

Comment on dimensions

It does not matter which number you use for length, width, or height. The problem is symmetrical that way, so any of the dimensions can be called any of those things. You need to use the same number consistently for height (for example) once you have made the choice of which is which.

the total estimated nappy use.=10,500,000

step-by-step explanation:

given that on an average the average baby uses 3528 napkins.

in a particular year 2014, the number of births were 299697 in new south wales.

rounding off the number of births to the nearest hundred thousand we have

no of birtsh = 300000

also rounding off the average usage to nearst thousand we get

average use of a baby = 3500

hence total number of nappy estimated to be used = 3500x300000

= 10,500,000

answer is 10,500,000 nappies