8 個解答
- ☂雨後晴空☀Lv 72 年前最愛解答
△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.
- SC147Lv 62 年前
∠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 )
- 匿名1 月前
△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.
資料來源: △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. - 3 月前
△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
資料來源: 我~很聰名巴(AND其他先解答的大大們) - 你覺得這個解答怎樣?你可以登入投選解答。
- 1 年前
△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
- 2 年前
△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.
- 匿名1 年前
The answer is B