Question

急死了,一个三角形abc,ab = 5,ac = 2√5,bc = √5 ,求三角形abc的面积?

Answer 1

因为,ab = 5, ac = 2√5, bc = √5,

所以,ac^2+ bc^2 =20+5=25,ab^2=5^2=25

所以,ac^2+ bc^2 =ab^2,

三角形abc是直角三角形,

所以三角形abc的面积=ac·bc=2√5·√5=2×5=10