Page 116 - NUMINO Challenge_D1
P. 116
Basic Concepts A Moving Circle
Observe carefully how the circle moves along its path. Observe whether it
moves in a straight or curved line while it changes direction.
A circle goes along the A circle goes along the
inner edges of a figure. outer edges of a figure.
The path has the same The circles move parallel to
shape as the figure. the figure, and then move in
a curved line at the edges.
Example A circle with a diameter of 2 cm is moving around
the perimeter of a square that has sides of 5 cm. It
made one complete turn around the square, and has
arrived back at the starting point. Find the total
distance the circle has traveled.
Class Notes
When the circle makes one complete turn around the square, the path of
the circle' s center is shown on the right.
The sum of the lengths of line segments on that path is equal to the
perimeter of the square, which is cm.
The sum of the lengths of curved parts is equal to the perimeter of
the circle. 2 cm.
Therefore, the center of the circle has moved cm.
Try It Again A circle with a radius of 1 cm is moving
along the edges of the surface, as
shown on the right. Find the distance 10 cm 10 cm
that the center of the circle has moved. 10 cm
113Measurement
Observe carefully how the circle moves along its path. Observe whether it
moves in a straight or curved line while it changes direction.
A circle goes along the A circle goes along the
inner edges of a figure. outer edges of a figure.
The path has the same The circles move parallel to
shape as the figure. the figure, and then move in
a curved line at the edges.
Example A circle with a diameter of 2 cm is moving around
the perimeter of a square that has sides of 5 cm. It
made one complete turn around the square, and has
arrived back at the starting point. Find the total
distance the circle has traveled.
Class Notes
When the circle makes one complete turn around the square, the path of
the circle' s center is shown on the right.
The sum of the lengths of line segments on that path is equal to the
perimeter of the square, which is cm.
The sum of the lengths of curved parts is equal to the perimeter of
the circle. 2 cm.
Therefore, the center of the circle has moved cm.
Try It Again A circle with a radius of 1 cm is moving
along the edges of the surface, as
shown on the right. Find the distance 10 cm 10 cm
that the center of the circle has moved. 10 cm
113Measurement
