Page 156 - NUMINO Challenge_D2

2 There are three colored cubes and one cube
which cannot be seen in the picture below.
4 cubes
Creative Thinking p.74~p.75
1 The number of cubes stacked on each square,
which is viewed from the top, is as shown below. The area of one side is 4 cm2, therefore the
There are no sides that cannot be seen from the
top and bottom, front and back, and right and
left side views.
44
31 3
2 1 12
411
The surface area is (6 6 9) 2 42 cm2.
2 200 cm2.
Top Front Side
The number of sides of 10 cubes is 10 6 60,
and the number of sides that can be seen from
the top and bottom, front and back, and right
side and left side is (6 6 6) 2 36.
Therefore, the sum of the surface areas of the
uncolored faces is 60 36 24 cm2.
3 The shape viewed from the top,
front, and side looks like a cube,
and there are six sides that
cannot be seen from the top,
front, and side as shown on the right. When you
add the number of sides that cannot be seen to
54 sides, you get 54 6 60 sides, therefore the
surface area is 60 cm2.
4 When the surface area is the smallest:
You can see nine sides from the top and six
sides each from the front and the side.
surface area is {(9 6 6) 2} 4 168 cm2.
When the surface area is the greatest:
Unseen Side
There are 10 sides from the top, eight sides
from the front, and six sides from the side that
can be seen, and two unseen sides. Therefore,
the surface area is {(10 8 6) 2 2} 4
9 Rotated Figures p.76~p.77
Example Axis of rotation Line symmetry
Answer Key