Google Classroom
GeoGebraGeoGebra Classroom

Rotations3_Finding Center

Instructions

ABC that has been rotated to form A'B'C'. But where is the center and what is the angle of rotation? 1. Construct the segments between the pre-image and the image. (Click Show Segments) 2. Construct the perpendicular bisectors of each segment.
  • Find the midpoints of each segment (click Show midpoints)
  • Construct a perpendicular line through each midpoint (click Show perpendicular lines)
3. Where do you think the center is located? (click Show center) 4. Uncheck all of the boxes from above or click the refresh icon. Keep the center of rotation visible. 5. Construct the angle of rotation between preimage, center, and image.
  • Click each checkbox individually to see the angle and its measurement. What do you notice about all the angle measurements?