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Are the points A (3, 6, 9), B (10, 20, 30) C (25, -41, 5). The vertices of a right angled triangle. |
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Answer» By distance formula, AB2 = (10 – 3)2 + (20 – 6)2 + (30 – 9)2 = 49 + 196 + 441 = 686 BC2 = (25 -10)2 + (- 41 – 20)2 + (5 – 30)2 = 225 + 3721 + 625 = 4571 CA2 = (3 – 25)2 + (6 + 41)2 + (9 – 5)2 = 484 + 2209 + 16 = 2709 We find that AB2 + CA2 ≠ BC2 (∵ 3395 ≠ 4571) ∴ ABC is not a right angled triangle. |
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