Rotations Exploration 1 - 90° (Teacher Copy)


Work with the teacher.

a. Draw a triangle with vertices at A(1,3) B(4,3), and C(4, 1). b. Create a point at the origin D(0,0). c. Rotate the triangle 90° counterclockwise about the origin to form triangle A'B'C'.

d. What is the relationship between the coordinates of the vertices of triangle ABC and those of triangle A'B'C'? Write a rule to determine the coordinates of the image of (x, y).

e. Find the side lengths and angle measures of the two triangles. What do you notice?