標題:
F.2 maths~[[congruent]]急急急急！！！
發問:
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http://xs315.xs.to/xs315/07193/cong.png 請睇圖,thanks
最佳解答:
1. 因為 △PQR congruent to △PRS, (SAS) (Reason: PR = PR (common side) QR = RS (Given) ∠PRQ = ∠PRS (Given) ) 所以 x = 10 cm y = 30° 2. (a) 3x + 4x + 5x = 180 => 12x = 180 => x = 15 (b) ∠R = 3x = 3x15 = 45° (c) Yes, they are congruent. Reason: AC = PR (Given) BC = RQ (Given) ∠R = ∠C = 45° So they are congruent (SAS)
其他解答:
1.In tri. PQR: cos.30=10/QR QR=10/cos.30 QR=11.54700538 QR=RS RS=11.54700538 sin.30=PR/10 PR=10sin.30 PR=5 In tri. PRS: tan.y=PR/RS tan.y=5/11.54700538 y=tan-15/11.54700538 y=23.42580861 cos23.42580861=PS/RS cos23.42580861=x/11.54700538 x=cos 23.42580861X11.54700538 x=10.59525984 2. 4x+5x+3x=180 (|||||因為有d符號電腦出唔到… 所以degree冇寫到…自己加番… 同埋congrent用左呢個-->≡ 第一題 ∵PR=PR (common sides) ∠PRQ = ∠PRS = 90 (given) QR = RS (given) ∴△PRQ ≡ △PRS (SAS) ∴ x = 10cm (corr. sides, ≡ △) y = 30 (corr.∠ ≡△) 第二題 a) 3x + 4x + 5x = 180 (∠sum of △) 12x = 180 x = 15 b) ∠R = 3(15) = 45 c) yes, because AC = PR and BC = QR, therefore the another sides must be congrent due to the reason of SSS
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