overleftrightarrow (AB) and overleftrightarrow (CD) are secants in the circle below. Chords formed by the points where the secants cross are color-coated below with their lengths.
成語: 文房四寶 [修訂本參考資料],注音: ㄨㄣˊ ㄈㄤˊ ㄙˋ ㄅㄠˇ,釋義: 筆、墨、紙、硯的合稱。因是書房中常備的四種東西,故稱為「文房四寶」。《三國演義》第三六回:「遂命左右捧過文房四寶,令徐母作書。
东边是哪里 - 文房四寶意思 -