Rectangular Coordinate System (I) 8.41
I. Reflection in the x-axis or y-axis
Take out the transparency film provided in the Activity Kit.
1. Follow the steps below and answer the question.
P(1,3)
-1-2-3 1
1
0 2 3
-1
-2
-3
2
3 y
x
Fig. A
-1-2-3 1
1
0 2 3
-1
-2
-3
2
3 y
x
P
-1-2-3 1
1
0 2 3
-1
-2
-3
2
3 y
x
y
x
O
P
y
x
O
P
1 unit
3 units
1 unit
3 units
Flip the film
along the
x-axis
Place the
film over
Fig. A
Denote the image of P by Pl.
(a) Distance between P and the x-axis =
Distance between Pl and the x-axis =
(b) P and Pl lie on a vertical line,
i.e. PPl is ( parallel / perpendicular ) to the x-axis.
(c) Coordinates of Pl = ( , )
2. Place the film over Fig. A so that their axes coincide respectively.
Flip the film along the y-axis. Denote the image of P by Pm.
(a) Distance between P and the y-axis =
Distance between Pm and the y-axis =
(b) P and Pm lie on a horizontal line,
i.e. PPm is ( parallel / perpendicular ) to the y-axis.
(c) Coordinates of Pm = ( , )
ActivityActivity
Class 8.5 Class e-Activity
If a perpendicular line segment is
drawn from point A to L and intersects
L at point B, then the length of AB is
the distance between A and L.
B
L
A
◀
Teachers may also use GeoGebra
to conduct the activity.
1
-1
3
1 3
1
-3
3