Page 164 - NUMINO Challenge_D1
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Measurement 3 (Length of the Electric Line) ( 4) 3.14
3.14 4 3.14
3.14 12.56
13 Perimeter and Area of a Circle p.112~p.113 (Perimeter of Earth) 3.14
The length of the electric line is 12.56 m longer
than the perimeter of Earth.
Example 10, 5 10, 10, 71.4
5, 5, 78.5
4 If the diameter of the original playground is , the
diameter of the new playground is ( 1) m.
(Perimeter of the original playground) 3.14
(Perimeter of the new playground) ( 1) 3.14
Example 20 3.14, 6.28 Therefore, the perimeter of the new playground
20, 6.28, 26.28
is 3.14 m greater than that of the original one.
Try It Again
9 cm 10 cm Problem solving
9 cm
1 The diameter of the circle that the center of the
The distance moved on the curved line is
equal to half the perimeter of the circle with quarter makes is 2.42 2.12 4.54 cm.
a radius of 1 cm. Therefore, the distance that the center of
the quarter has moved is 4.54 3.14 10
(9 9 10 9 9) (1 2 3.14 2) 142.556 cm.
46 3.14 49.14 cm
2 In the picture, the straight line sections on the
Type 13-1 Increasing Perimeter of a Circle p.114~p.115
inner and outer tracks have equal lengths. Since
1 The diameter of the circle connected by the the diameter of the outer track is 4 m longer
electric line is 4 m longer. than that of the inner track, the curved section
on the outer track is 4 3.14 12.56 cm longer.
2m 2m Therefore, the outer track measures
400 12.56 412.56 m.
Type 13-2 A Cow Tied to a Fence p.116~p.117
2 Since the diameter of Earth is , its perimeter is 1 The radius of the big circle is equal to the length
3.14. The diameter of the circle connected by
of the rope.
the electric line is 4, therefore, the perimeter
of the circle is ( 4) 3.14. 3 , 5m
4
2 (Length of the rope) (horizontal length of the
fence) (radius of the blue part)
1 , 1m
4
Answer Key
3.14 4 3.14
3.14 12.56
13 Perimeter and Area of a Circle p.112~p.113 (Perimeter of Earth) 3.14
The length of the electric line is 12.56 m longer
than the perimeter of Earth.
Example 10, 5 10, 10, 71.4
5, 5, 78.5
4 If the diameter of the original playground is , the
diameter of the new playground is ( 1) m.
(Perimeter of the original playground) 3.14
(Perimeter of the new playground) ( 1) 3.14
Example 20 3.14, 6.28 Therefore, the perimeter of the new playground
20, 6.28, 26.28
is 3.14 m greater than that of the original one.
Try It Again
9 cm 10 cm Problem solving
9 cm
1 The diameter of the circle that the center of the
The distance moved on the curved line is
equal to half the perimeter of the circle with quarter makes is 2.42 2.12 4.54 cm.
a radius of 1 cm. Therefore, the distance that the center of
the quarter has moved is 4.54 3.14 10
(9 9 10 9 9) (1 2 3.14 2) 142.556 cm.
46 3.14 49.14 cm
2 In the picture, the straight line sections on the
Type 13-1 Increasing Perimeter of a Circle p.114~p.115
inner and outer tracks have equal lengths. Since
1 The diameter of the circle connected by the the diameter of the outer track is 4 m longer
electric line is 4 m longer. than that of the inner track, the curved section
on the outer track is 4 3.14 12.56 cm longer.
2m 2m Therefore, the outer track measures
400 12.56 412.56 m.
Type 13-2 A Cow Tied to a Fence p.116~p.117
2 Since the diameter of Earth is , its perimeter is 1 The radius of the big circle is equal to the length
3.14. The diameter of the circle connected by
of the rope.
the electric line is 4, therefore, the perimeter
of the circle is ( 4) 3.14. 3 , 5m
4
2 (Length of the rope) (horizontal length of the
fence) (radius of the blue part)
1 , 1m
4
Answer Key
