599. 36 см 8 мм + 9 мм

To solve this problem, we need to add the lengths given. First, we add the millimeters: 8 mm + 9 mm = 17 mm. Then, we add the centimeters: 36 cm. Since 17 mm is equal to 1 cm and 7 mm, we carry over 1 cm to the centimeter sum. So, 36 cm + 1 cm = 37 cm. The total length is 37 cm and 7 mm.