What theorem or postulate can you use to find the measure of angle A in the diagram below without using the Exterior Angle Theorem?

a. Same-side interior angles theorem
b. Linear pair postulate
c. Corresponding angles postulate
d. Right angles theorem
(IMAGE BELOW)

Question

What theorem or postulate can you use to find the measure of angle A in the diagram below without using the Exterior Angle Theorem?

a. Same-side interior angles theorem
b. Linear pair postulate
c. Corresponding angles postulate
d. Right angles theorem
(IMAGE BELOW)

justmeandme · Answer

attachment

jiteshmeghwal9 · Answer

not sure but i think linear pair postulate

mathmate · Answer

You will need the sum of angles of a triangle theorem https://www.mathsisfun.com/proof180deg.html and one of the above choices. To make right choice, you will need to know all of the above theorems, here are some links to help you. In elementary geometry, knowing the definition of theorems will often help you identify solution, that is the reason for this exercise to prepare you for future proofs. Do not shortcut yourself by having someone give you the answer to this question, and hence render your later exercises more difficult. http://jwilson.coe.uga.edu/EMAT6680/Dunbar/Math7200/ParallelLines/parallel_sameside.htm http://planetmath.org/linearpair http://hotmath.com/hotmath_help/topics/corresponding-angles-postulate.html https://en.wikipedia.org/wiki/Right_angle#Thales.27_theorem (note: the right angles theorem could refer to Thales theorem above or Pythagoras theorem).