Răspuns:
Explicație pas cu pas:
a = 10 ; b = 5 ; c = √50 = 5√2
a² = b²+c²-2bc· cos A => cos A = (b²+c²-a²)/ 2bc
cos A = (5²+(√50)² - 10²) / 2·5·5·√2
cos A = (25+50-100)·√2/100 = -√2/4 => ∡A ≈111°
b² = a²+c²-2ac·cosB => cos B = (a²+c²-b²)/2ac
cos B = (100+50 -25)·√2/200 = 5√2/8 => ∡B = 28°
c² = a²+b²-2ab- cos C => cos C = (a²+b²-c²)/2ab
cos C = (100+25-50)/100 = 3/4 => ∡C ≈ 41°
