Question: for helical gear the helix angle generally ranges from
[{'answer': '15 ° to 30 °', 'provenance': [{'wikipedia_id': '13006958', 'title': 'Helix angle', 'start_paragraph_id': 16, 'start_character': 179, 'end_paragraph_id': 16, 'end_character': 193, 'bleu_score': 1.0, 'section': 'Section::::Applications.:Helical gear.\n'}]}, {'provenance': [{'wikipedia_id': '13006958', 'title': 'Helix angle', 'start_paragraph_id': 16, 'start_character': 0, 'end_paragraph_id': 16, 'end_character': 465, 'bleu_score': 0.9748377259086851, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 4405725043083473889}, 'section': 'Section::::Applications.:Helical gear.\n'}]}]