Maths problem, thanks?
回答 (8)
2019-08-13 12:53 am
✔ 最佳答案
△ABC : △ADE = AC : AE △ABC : 1 = (AC/AD) : (AE/AD)
△ABC = (1/cos60°) : cos60°
△ABC = 2 : 1/2
△ABC = 4 cm²
The answer is B.
2019-08-12 11:32 pm
∠B=∠E=90⁰
∠BAC=30⁰=∠EDA
∠BCA=60⁰=∠EAD
∴ △ABC ～ △DEA (AAA)
=> area of △ABC ：area of △DEA =AC² ：DA²
=> area of △ABC ：1 = AC² ：DA²
=> area of △ABC = (AC/DA)² . . . . . . . . . . . . . . . ①
DA
From rt-angled △ADC, cos 60⁰ = ------
AC
½ = DA/AC
From ①： area of △ABC = (2/1)² = 4 (ans : B )
∠BAC=30⁰=∠EDA
∠BCA=60⁰=∠EAD
∴ △ABC ～ △DEA (AAA)
=> area of △ABC ：area of △DEA =AC² ：DA²
=> area of △ABC ：1 = AC² ：DA²
=> area of △ABC = (AC/DA)² . . . . . . . . . . . . . . . ①
DA
From rt-angled △ADC, cos 60⁰ = ------
AC
½ = DA/AC
From ①： area of △ABC = (2/1)² = 4 (ans : B )
2019-12-30 3:39 pm
△ABC : △ADE = AC : AE
△ABC : 1 = (AC/AD) : (AE/AD)
△ABC = (1/cos60°) : cos60°
△ABC = 2 : 1/2
△ABC = 4 cm²
The answer is B
△ABC : 1 = (AC/AD) : (AE/AD)
△ABC = (1/cos60°) : cos60°
△ABC = 2 : 1/2
△ABC = 4 cm²
The answer is B
2021-01-24 9:25 pm
△ABC : △ADE = AC : AE
△ABC : 1 = (AC/AD) : (AE/AD)
△ABC = (1/cos60°) : cos60°
△ABC = 2 : 1/2
△ABC = 4 cm²
The answer is B.
△ABC : 1 = (AC/AD) : (AE/AD)
△ABC = (1/cos60°) : cos60°
△ABC = 2 : 1/2
△ABC = 4 cm²
The answer is B.
參考: △ABC : △ADE = AC : AE
△ABC : 1 = (AC/AD) : (AE/AD)
△ABC = (1/cos60°) : cos60°
△ABC = 2 : 1/2
△ABC = 4 cm²
The answer is B.
2020-12-07 6:58 pm
△ABC : △ADE = AC : AE
△ABC : 1 = (AC/AD) : (AE/AD)
△ABC = (1/cos60°) : cos60°
△ABC = 2 : 1/2
△ABC = 4 cm²
The answer is B
△ABC : 1 = (AC/AD) : (AE/AD)
△ABC = (1/cos60°) : cos60°
△ABC = 2 : 1/2
△ABC = 4 cm²
The answer is B
參考: 我~很聰名巴(AND其他先解答的大大們)
2019-08-19 9:47 pm
△ABC : △ADE = AC : AE
△ABC : 1 = (AC/AD) : (AE/AD)
△ABC = (1/cos60°) : cos60°
△ABC = 2 : 1/2
△ABC = 4 cm²
The answer is B.
△ABC : 1 = (AC/AD) : (AE/AD)
△ABC = (1/cos60°) : cos60°
△ABC = 2 : 1/2
△ABC = 4 cm²
The answer is B.
2019-08-12 8:18 pm
△ADE ～ △CAB
area△ADE : area△ABC = AD ² : AC ² = 1² : 2² = 1 : 4
4cm²
B. #
area△ADE : area△ABC = AD ² : AC ² = 1² : 2² = 1 : 4
4cm²
B. #
2020-03-03 12:46 pm
The answer is B
收錄日期: 2021-04-11 22:58:32
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20190812111840AAvyAUT