If a magnified image of a snowflake is 15 cm, how large is it in real life?

Idk but here is something about snowflakes:
Another marvel is the very symbol of winter itself—the snowflake. These extremely fragile crystals keep their six-sided shapes as they fall thousands of feet through gray skies. Snowflakes are lacy growths of water vapor formed around minute dust particles in the air. While we do not normally notice this dust, we can see it when it is caught in the shaft of a sunbeam. At the right temperature, when a water vapor molecule attaches itself to a dust nucleus, a snowflake is born. It takes on remarkable shapes as it plunges earthward. Some shapes are delightfully simple and others are fantastically complex, but no two are precisely alike. Some snow crystals form the most beautiful designs in the world. The exquisite lacelike patterns have often been copied for jewelry pieces and fabric designs. “It is a wonder of wonders that the dance of the molecules produces these geometrical designs,” said one authority about the snowflake.
Usually snowflakes fall individually, but if the temperature is just above freezing, they might cling together as they fall, sometimes forming a flake four inches in diameter. When enough snow falls, an unusual amount of air is trapped within snow crystals. Men have been known to survive two days buried in snow without suffocating. Because of its air-holding potential, snow makes an excellent insulator, keeping heat in the lower ground levels and preserving seeds from freezing and winter crops from being destroyed. How useful this beautiful winter wonder!