(1) perimeter A+B+C = √ 2+ 1, a+b=√2C+C = √ 2+ 1, so c= 1 and A+B = √ 2.

(2) △ ABC = 0.5 * a * b * sinc =1/6 sinc area, so a*b= 1/3, and because a+b=√2, so a 2+b 2 = 2-2/3 = 4/.

According to the cosine theorem, COSC = (A2+B2-C2)/(2AB) =1/2.