Since the two base angles are congruent (same measure), they are each 70°. If we are given a base angle of say 45°, we know the base angles are congruent (same measure) and the interior angles of any triangle always add to 180°.
Answer: Out of 7 bottles, 2 bottles contain soda. This means that 2 bottles= 29% out of 100%. 7/2 (7 divided by 2) = 0.285. 0.285 can be rounded up to 0.29, meaning that the approximate percentage of the bottles that contain soda is 29%.