Alice is making an octahedron out of origami. The last step requires her to blow into the octahedron to fill it up. A square pyramid on top of an upside down square pyramid the same size. The length of each side of the square base is a and the height of each pyramid is b. Which expression represents the volume of air she will need to inflate the octahedron?

Given: lines a and b are parallel and line c is a transversal. prove: 2 is supplementary to 8 what is the missing reason in the proof? statement reason 1. a || b, is a transv 1. given 2. ∠6 ≅ ∠2 2. ? 3. m∠6 = m∠2 3. def. of congruent 4. ∠6 is supp. to ∠8 4. def. of linear pair 5. ∠2 is supp. to ∠8 5. congruent supplements theorem corresponding angles theorem alternate interior angles theorem vertical angles theorem alternate exterior angles theorem