If you have a triangle one side is 7 cm and one side is 13 cm what is the length of the missing side?

I don't think there is enough information to answer the question, first of all, is it a right triangle? Second, is the the 13cm the hypotenuse. Assuming that 13cm is the hypotenuse, and the triangle is a right triangle, the equation would be 49+x^2=169