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標題:
trigo. problem
發問:
suppose a:b:c = 3:7:9 find the large angle of 三角形ABC
最佳解答:
Let a = 3k, b = 7k and c = 9k By ∠ sum of Δ, 3k + 7k + 9k = 180 19k = 180 k = 180/19 The largest angle of ΔABC = 9(180/19) = 1620/19 (~85.3 deg, corr. to 3 sig. fig.)
其他解答:
suppose a：b：c = 3：7：9 find the large angle of 三角形ABC Sol Cosw =(3^2+7^2-9^2)/(2*3*7) =(9+49-81)/42 =-23/42 w=123.2度
trigo. problem
發問:
suppose a:b:c = 3:7:9 find the large angle of 三角形ABC
最佳解答:
Let a = 3k, b = 7k and c = 9k By ∠ sum of Δ, 3k + 7k + 9k = 180 19k = 180 k = 180/19 The largest angle of ΔABC = 9(180/19) = 1620/19 (~85.3 deg, corr. to 3 sig. fig.)
其他解答:
suppose a：b：c = 3：7：9 find the large angle of 三角形ABC Sol Cosw =(3^2+7^2-9^2)/(2*3*7) =(9+49-81)/42 =-23/42 w=123.2度
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