Height cm  Weight kg  

Height 184 weight 39
What is the ideal weight for 184 cm tall male or female? Is it normal to weigh 39 kg for this height? Body Mass Index (BMI) will answer these questions. If BMI value is within the range 18.5 – 24.99 (for any height), then the weight is withing normal limits.
For the height 1.84 meters (184 cm) and for the weight 39 kilograms:  

Result:  Significant lack of weight. 
BMI:  11.52 
Normal weight limits:  63  84 kg. 
What to do?  Gain 24 kg. 
How to calculate BMI and weight ranges on your own?
 BMI formula: weight / height^{2}
 where the height value is in meters (not in centimeters), for example 1.7 (not 170).
 Multiplication first, then division!  For example, if the height is 166 cm and the weight is 61 kg, then BMI = 61 / 1.66 * 1.66 = 22.14. BMI within normal values.
Check yourself. The Height and weight combinations below are normal or not?