The diagonals of the rhombus are 1.6 cm and 3 cm. What is the side of this rhombus?

The problem is given a rhombus ABCD, its diagonals AC = 1.6 cm, BD = 3 cm, the point of intersection of the diagonals O.
The diagonals of the rhombus are mutually perpendicular, and each of them is halved by the point of intersection:
AO = ½ AC = 0.8 cm,
OB = ½ BD = 1.5 cm,
Angle AOB = 90 °.
By the Pythagorean theorem, we find the side of the rhombus AB, which in the triangle AOB is the hypotenuse:
AB ^ 2 = AO ^ 2 + OB ^ 2;
AB ^ 2 = (0.8) ^ 2 + (1.5) ^ 2;
AB ^ 2 = 0.64 + 2.25;
AB ^ 2 = 2.89
AB = √2.89;
AB = 1.7 cm.