Page 71 - NUMINO Challenge_D2
P. 71
8 Cubes and Surface Area
Basic Concepts The Surface Area of Stacked Cubes
To find the surface area of a solid figure made up of cubes that have 1 as
the area of each face, multiply the number of faces seen from the top, front,
and side views by 2. Then, add the number of faces that cannot be seen
from the top, front, and side views.
Top
Side
Top Front Side
(8 faces) (7 faces) (6 faces)
Front
(Surface area of the stacked cubes)
(8 7 6) 2 2 44
As shown on the solid figure on the right, the faces colored
in red cannot be seen from the views when finding the surface area.
Therefore, be careful not to miss out these faces.
Example The following solid figure is made up of cubes that are stacked as
shown below. The length of each side of the cube is 1 cm. What is
the surface area in cm2?
Class Notes
The following shows the top, front, and side views of a solid figure.
Therefore, the total number of faces seen from top and bottom, front and back,
and left and right, is 5 6 ) .
Top Front Side
The red colored faces shown on the right cannot be seen from the top,
front, and side views. Therefore, if you add to the number of
faces found from , you can find the total number of faces.
Since the area of each face of the cube is 1 cm2, the surface area of
the solid figure is cm2.
68 NUMINO Challenge D2
Basic Concepts The Surface Area of Stacked Cubes
To find the surface area of a solid figure made up of cubes that have 1 as
the area of each face, multiply the number of faces seen from the top, front,
and side views by 2. Then, add the number of faces that cannot be seen
from the top, front, and side views.
Top
Side
Top Front Side
(8 faces) (7 faces) (6 faces)
Front
(Surface area of the stacked cubes)
(8 7 6) 2 2 44
As shown on the solid figure on the right, the faces colored
in red cannot be seen from the views when finding the surface area.
Therefore, be careful not to miss out these faces.
Example The following solid figure is made up of cubes that are stacked as
shown below. The length of each side of the cube is 1 cm. What is
the surface area in cm2?
Class Notes
The following shows the top, front, and side views of a solid figure.
Therefore, the total number of faces seen from top and bottom, front and back,
and left and right, is 5 6 ) .
Top Front Side
The red colored faces shown on the right cannot be seen from the top,
front, and side views. Therefore, if you add to the number of
faces found from , you can find the total number of faces.
Since the area of each face of the cube is 1 cm2, the surface area of
the solid figure is cm2.
68 NUMINO Challenge D2
