有些中一數學問題不懂
希望各位幫忙解答
1. Given that the interior angles of a triangle are X-15度, X-25度 and 1/2X-10度 respectively. Find X.
2. In △ABC, ∠C is twice the sum of ∠A and ∠B. Find ∠C.
請懂的幫個忙，我不太明白怎樣解，謝謝！
中一數學問題(急！)關於角度及三角形等問題
2009-02-04 1:21 am
回答 (2)
2009-02-04 1:37 am
✔ 最佳答案
1. (X-15)+(X-25)+(X/2-10) = 180X-15+X-25+X/2-10 = 180
2X-50+X/2 = 180
2X + X/2 = 180+50
4X + X = 230*2
5X = 460
X = 460/5
X = 92
2. ∠A +∠B+∠C = 180 ... (1)
∠C = 2 * (∠A +∠B) ... (2)
FROM (1),
∠A +∠B = 180 - ∠C ... (3)
SUB (3) into (2)
∠C = 2 *(180 - ∠C)
∠C = 360 - 2∠C
3∠C = 360
∠C = 120
2009-02-04 1:26 am
Are you in English scool ? I am ! So I can Help you !
SEE, if X = 15, the sum is 56. If X= 69, the sum is 46. understand ? Yes !
SEE, if X = 15, the sum is 56. If X= 69, the sum is 46. understand ? Yes !
參考: Hope can help you
收錄日期: 2021-04-23 23:13:18
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20090203000051KK01709