Fri. 11/01/13

GG.35 Parallel and intersecting lines

UR Group: Henry, Alex, Isabel, & Richard

M<1 = (2x + 12)° M<2 = (3x + 18)° Henry: [wrote on a w/board] values that were given Isabel: [Sp]……. Richard: She said she want to try it

Isabel’s solution

Henry: No, is not like thatIsabel: [Sp……]Alex: she said, that was how she learned it in DR

Henry: We need to know the relationship between the angles. They are both interior angles[look point to the text] they add up to 180°

Henry: [wrote] m< 1 + m< 2 = 180°But: m<1 = 2x + 12 and m<2 = 3x + 18 2x + 12 + 3x + 18 = 180°

m<1 = 2x + 12 m<2 = 3x + 18

(2x + 12) + (3x + 18) = 180°

Henry: We have to combine like terms. Who willcontinue?

Alex: 2x + 12 + 3x + 18 = 180° 2x + 3x + 12 + 18 = 180° 5x + 30 = 180°

pausedHenry: Let me finish it

Richard: Is that the final answer?Henry: No, we put x into m<1 = (2x + 12) = (2 * 30 + 12) = (60 + 12) = 72° m<2 = (3x + 18) = (3 * 30 + 18) = (90 + 18) = 108°

Take away

• The group identified that interior angles on the same side of the transversal are supplementary (180°)

The group followed the rules of the format by: Being responsive to the comment of their peers.

Neither dominate conversation nor refrain from participation.