Could 7.7\text{ cm}, 4.0\text{ cm},7.7 cm,4.0 cm,7, point, 7, space, c, m, comma, 4, point, 0, space, c, m, comma and 1.7\text{ cm}1.7 cm1, point, 7, space, c, m be the side lengths of a triangle?

No, they could not be the sides of a triangle.the triangle inequality theorem states that the sum of the smallest two sides of any triangle must be larger than the largest side.  the smallest two sides here are 1.7 and 4; 1.7+4 = 5.7.  this is not long enough; it must be longer than 7.7.