{"book":"adl0946","page":217,"text":"۲۱۰\nپس می گوئیم\nقضیه - مجموع زوایای هر کثیرالاضلاع محدّب\nمساوی است با آن قدر دو قائمه که عدد اضلاع\nیا شد منهای دو\nمثلاً مجموع زوایای مسبع چنین است\n۲ x ۵ = ۱۰\nدر چهار ضلعی چنین ۴ = ۲ x ۲\nو مثلث چنین ۲ = ۱ x ۲\nو غیره\n۴۲ - نتیجه - سابقاً در ۱۴۹ ثابت کردیم که هر گاه\nدر مثلثی دو ضلع مساوی باشند زوایای مقابل به آنها هم مساویند\nو در ۱۵۲ عکس آن را به ثبوت رسانیدیم حال بسهولت\nممکن است مطالب ذیل را اثبات نمود -\nهرگاه در مثلثی دو ضلع غیر مساوی باشد\nدو زاویهٔ مقابل بآنها هم غیر مساویند.","chars":479,"image":"https://storage.googleapis.com/adl-page-images/adl0946/00217.jpg","first_page":1,"last_page":327,"title":"Handasah-ʼi musaṭṭaḥah barā-yi ṣinf-i haftum-i makātib-i rushdīyah, bi-qarār-i prūghram-i Vizārat-i Jalīlah-ʼi Muʻārif-i Afghānistān هندسۀ مسطحه :هندسۀ مسطحه","permalink":"https://afghanpress.org/book/adl0946/217","canvas":"https://afghanpress.org/iiif/adl0946/canvas/217","source":"https://afghanistandl.nyu.edu/books/adl0946/","source_pdf":"https://afghanistandl.nyu.edu/pdf/adl0946_download.pdf","rights":{"image":{"statement":"Public domain. NYU states: \"All works presented on this website are, unless otherwise indicated, in the public domain. The images available on this website may be freely reproduced, distributed and transmitted by anyone for any purpose, commercial or non-commercial.\"","uri":"http://rightsstatements.org/vocab/NoC-US/1.0/","holder":"New York University Libraries","source":"https://afghanistandl.nyu.edu/about.html","delivery":"Images are served from a copy mirrored by this project, not from NYU's servers, under the reproduction terms above.","endorsement":"This is an independent project. It is not affiliated with, endorsed by, or reviewed by New York University."},"text":{"statement":"Machine-generated transcription, dedicated to the public domain under CC0 1.0. No warranty of accuracy: see the provenance block on every page.","uri":"https://creativecommons.org/publicdomain/zero/1.0/","holder":"Steps Ventures"}},"provenance":{"text_produced_by":"gemini-3.1-pro-preview","thinking_level":"low","read_completed":"2026-08-09","per_page_confidence":null,"per_page_confidence_note":"Not recorded during the corpus run. No calibrated per-page score exists, and none is estimated here.","human_reviewed":false,"accuracy_context":"Roughly two thirds of characters agree with a modern printed edition of the same text. Much of the disagreement is editorial, not misreading. Treat the transcription as a finding aid and read the page image before quoting.","primary_source":"The page image. The text is an index into it."}}