Transcript Glencoe Pre

You drew translations and reflections on the
coordinate plane. (Lesson 2–7)
• Define, identify, and draw rotations.
• Determine if a figure has rotational
symmetry.
• rotation
• center of rotation
• rotational symmetry
Rotate a Figure about a Point
Draw the figure shown after a 90° clockwise
rotation about point A.
Answer:
Point A stays in the same
position. The figure moves one
quarter turn clockwise.
'
Which figure is a 270° clockwise
rotation of the figure about point S?
A.
B.
C.
D.
A.
B.
C.
D.
A
B
C
D
Rotate a Figure about a Point
Triangle EFG has vertices E(2, 1), F(1, –1) and
G(4, –1). Graph the figure and its image after a
clockwise rotation of 90° about vertex F. Then give
the coordinates of the vertices for triangle E'F'G'.
Rotate a Figure about a Point
Step 2 Graph the remaining vertices after 90° rotations
around vertex F. Connect the vertices to form
triangle E'F'G'.
Answer: E'(3, –2), F'(1, –1), and G'(1, –4)
In the figure, triangle ABC has
been rotated about point A to form
triangle A'B'C'. How many degrees
was it rotated?
A. 90°
B. 180°
C. 270°
D. 360°
A.
B.
C.
D.
A
B
C
D
Rotations about the Origin
Parallelogram ABCD has vertices A(–3, –1),
B(1, –2), C(–1, –4) and D(–5, –3). Graph the
parallelogram and its image after a rotation
of 180° about the origin.
Rotations about the Origin
Step 2 Graph the remaining vertices after 180°
rotations around vertex A. Connect the
vertices to form parallelogram A'B'C'D'.
Answer:
A' (3, 1), B' (–1, 2), C' (1, 4), D' (5, 3)
Triangle XYZ has vertices X(–3, 1), Y(0, –2), and
Z(4, 3). Find the coordinates of the vertices after a
rotation of 180° about the origin.
A. X'(3, –1), Y'(0, 2), Z'(–4, –3)
B. X'(1, –3), Y'(–2, 0), Z'(3, 4)
C. X'(–1, 3), Y'(2, 0), Z'(–3, –4)
D. X'(–3, –1), Y'(0, –2), Z'(4, –3)
A.
B.
C.
D.
A
B
C
D