සා/පෙළ ගණිතය 2021 ප්‍රශ්න පත්‍රය

Value of an item after adding a percentage customs duty

පිළිතුර: Rs 9,760

💡 ප්‍රශ්නයේ අදහස: තීරු බද්ද යනු මිලට උඩින් එකතු වන අමතර මුදලකි. වටිනාකමෙන් 22% සොයා එය එකතු කරමු.

1. 18000 න් 22% සොයන්න: 8000 × 22 ÷ 100 = 1760.
2. 2එය මුල් වටිනාකමට එකතු කරන්න: 8000 + 1760 = 9760.
3. 3එබැවින් බද්දෙන් පසු වටිනාකම රු. 9760.

✅ පිළිතුර රු. 8000 ට වඩා ටිකක් (පහෙන් පංගුවක් පමණ) වැඩි විය යුතුය; 9760 එසේය.

Use isosceles triangle base angles and angle sum

පිළිතුර: x = 36°

💡 ප්‍රශ්නයේ අදහස: ත්‍රිකෝණයේ පාද දෙකක් සමාන නිසා ආධාරක කෝණ දෙකත් සමානයි. කෝණ තුනේ එකතුව 180° කි.

1. 1සමාන පාදවලට ඉදිරියෙන් ඇති නිසා ආධාරක කෝණ දෙකම 2x වේ.
2. 2කෝණ සියල්ල එකතු කරන්න: x + 2x + 2x = 5x.
3. 35x = 180° ලෙස තබා 5 න් බෙදන්න: x = 36°.

✅ 36° + 72° + 72° = 180° නිසා නිවැරදියි.

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