Respuesta :
Answer:
9
Step-by-step explanation:
The surface, in this case, describes the number of squares that are painted. On the left hand side, we have a cube, so we know we're going to have 6 faces. And each face on the cube has 9 little squares, they can be counted on the diagram. So, the total number of squares that are painted on the left cube = [tex]9 * 6 = 54[/tex]
The star means multiplication.
We are told in the question that it takes 9 litres of paint to cover the surface of the left hand cube, meaning it takes 9 litres of paint to cover 54 squares.
This can be written in the ratio = [tex]9:54[/tex]
If we divide both sides of the ratio by 9, we can figure out the amount of squares that 1 litre of paint covers, [tex]1:6[/tex].
The ratio tells us that 1 litre of paint covers 6 squares.
Let's look at the shape on the right. It is still a cube, however, some segments have been removed. Some faces still remain the same as in the shape on the left, such as the bottom face, the back face and the face to the left. Those faces may not be so apparent on the diagram, however, they exist. So we have to count them.
The number of small squares on these faces = [tex]9 * 3=27[/tex]
If you look on the inside of the cube, which can be seen on the diagram, we can see three faces, each having four squares. So, the total number of squares here = [tex]3*4=12[/tex]
Also, we have some squares on the top, and if you count these, there are 5.
This also applies for the front and the right hand side if you count, so we add 10 squares to the total as there are another two lots of five.
So, the total number of squares on the right cube = [tex]27 + 12 + 5 + 5 + 5 = 54[/tex]
Let's bring back the ratio of litres of paint to the number of squares covered: [tex]1:6[/tex]
In the ratio, there are 6 squares per litre. We know that 6 × 9 = 54 (our total). So, we multiply left hand side of the ratio by 9 as well, bringing the total amount of paint required to 9 litres.
I hope this helps.
The surface area of cuboid = [tex]$400 \mathrm{~cm}^{2}$[/tex].
How to estimate the surface area of cuboid?
If the left cube takes 9 liters of paint to cover the surface. Then, also right cube takes 9 liters of paint to cover the surface.
Cuboid dimension [tex]$\frac{10 \mathrm{~cm}}{(l)} \times \frac{10 \mathrm{~cm}}{(b)} \times\frac{5 \mathrm{~cm}}{(h)}$[/tex]
Surface area = 2(lb + lh + bh)
= 2((10 [tex]\times[/tex] 10)+(10 [tex]\times[/tex] 5)+(10 [tex]\times[/tex] 5))
= 2(100+50+50)
= [tex]400 \mathrm{~cm}^{2}[/tex]
Therefore, surface area of cuboid = [tex]$400 \mathrm{~cm}^{2}$[/tex].
To learn more about surface area of cuboid
https://brainly.com/question/26403859
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