Respostas

2014-02-28T19:41:12-03:00
A2=b2+c2-2bc . cosÂ
a2=25+64-8.1/2
a2=89-80/2
a2=178-80/2
a2=98/2
a2=49
a=V49 (raiz de 49)
a=7 cm