In the diagram, line x is parallel to line y, m21= 65°, and m27 = 55°. Stuart says that m212 = 60°. His reasoning is shown. Step 1: mZ8 = 60°, because m21+ m27 +m28 = 180º. Step 2:28 212, because 28 and 212 are corresponding angles. Step 3: So, mZ12 = 60° Use the drop-down menus to explain whether or not Stuart is correct.

The reasoning that may be used for finding the measure of m∠12, is the

same side interior angles theorem.

The correct options using the drop-down menu are;

Reasons:

Given parameters;

Line x ║ line y

m∠1 = 65°, m∠7 = 55°

m∠12 = 60°

Stuart states ∠12 = 60°

The reasoning is presented as follows;

Step 1: m∠8 = 60°, because m∠1 + m∠7 + m∠8 = 180°

Step 2: ∠8 ≅ ∠12, because ∠8 and ∠12 are corresponding angles

Step 3: So, m∠12 = 60°

Using the drop-down menu, we have;

The sum of ∠1, ∠7, and ∠8 is 180° (Sum of angles in the triangle)

∠8 and ∠12 are same side interior angles (by definition)

Same side interior angles are supplementary, therefore;

∠8 +∠12 = 180°

∠12 = 180°  - ∠8

Which gives;

The measure of ∠12 must be 180° - ∠8 = 180° - 60° = 120°

The measure of ∠12 must be = 120°

Stuart is not correct

Learn more about angles formed between parallel lines and a transversal here:

link

180, same side interior, 120, incorrect

Step-by-step explanation:

Seeing that the other person failed to answer the question at all and made a worthless topic answer.  I went ahead and solved it.

So all you have to know that sets stuart wrong is that angle 12 is not 69 degrees. So the dropdowns as follows. Angle 1, 7 and 8 make one triangle and have equal degrees. So 180 equals a whole triangle. Angle 12 and 8 are on the same side and inside the triangle. (Remember 1,7,8? well divide 180 by 3 and u get angle 8 being 60. Same as angle 7. The interior trapezoid will be 60+60+120+120=360.) Angle 12= 120 thus Stuart is wrong.

i believe the answer is the polygon, heptagon.

step-by-step explanation: