Investigation 1 Douglas

Place your mouse on point B. Move point B up and down. A. Record the angle measurements for angles <DEB, <DAE, <AEC, and <CEB for 10 movements. B. Write down three things that you notice as the picture changes. C. Make an observation (conjecture) about the red/blue angles. Is your conjecture always true?
Use points A, B, C, and D to change the angle values. Make a conjecture about the angle measures of a pair of vertical angles.