marada
幼苗
共回答了20个问题采纳率:70% 举报
1.Rt△ABC中(a^2 表示 a 的平方)
(1) a :b = 3 :4 ,那么 a :b :c = 3 :4 :5 ;
c = 75cm ,那么 a = 45cm ,b = 60cm
(2) a :c = 15 :17 ,那么 a :b :c = 15 :8 :17;
b = 24 ,那么 a = 45 ,S = (1 / 2) * a b = 540
(3) c - a = 4 ,a + 4 = c ,c^2 = a^2 +b^2 ,所以 a = 30 ,c = 34
(4) ∠A = 30° ,2 a = c ,所以 a = 12 ,b = 12 √3;
hc = (1 / 2)b = 6 √3
(5) abc 为连续整数 ,c = a + 2 ,b = a + 1,c^2 = a^2 +b^2 ;
所以 a = 3 ,a + b + c = 3 a + 3 = 12 .
2.看不到图
1年前
5