Aconjecture and the paragraph proof used to prove the conjecture are shown. given: angle 1 is congruent to angle 4. prove: angle 2 is congruent to angle 3. two rays share an endpoint. two similar rays opposite in direction share another end point just opposite to the previous endpoint. the obtuse angle made by the upper rays in outward direction is labeled 1. the obtuse angle made by the lower rays in outward direction is labeled 4. the obtuse angle made by the upper rays in inward direction is labeled 2. the obtuse angle made by the upper rays in inward direction is labeled 3. drag an expression or statement to each box to complete the proof. it is given that ∠1≅ ∠4 . by the vertical angle theorem, ≅∠1 . therefore, ∠2≅∠4 by the substitution property. by the , ∠4≅∠3 . so, ∠2≅ by the .