A.90°之對(duì)邊長(zhǎng) B.60°之對(duì)邊長(zhǎng) C.30°之對(duì)邊長(zhǎng) D.三角板之斜邊
A.1:2 B.2:1 C.1:1 D.以上皆非
A.2 B.2.5 C.3.5 D.5