Lines and Angles

Grade 9s are working hard to review all their analytic geometry skills before their summative tomorrow.

We graphed lines from an equation (6x-2y=4) that we needed to rearrange first. We looked at calculating the x and y intercepts using various reasoning strategies using proportions, and also by substituting in zero for x or y and calculating the other.

We drew another line that was parallel (same slope) but different y intercept. We looked at how to calculate the x and y intercepts.

Next we drew a line through 2 given points (-5,8) and (3,-6). We calculated the slope, and the y intercept and then graphed the lines. Our last step was to label the angles and cut along the parallel lines and the transversal.

We noticed the acute angles we made are all congruent….so are the obtuse angles.

These angles are also supplementary (add to 180 degrees).