If you wanted to measure your body composition and only had a scale and measuring tape, how do you measure your body?

I can use body mass index, waist circumference, and waist-to-hip ratio

Explanation:

With a scale and a measuring tape, I can get a rough indication of my body composition by calculating my Body Mass Index.

Body Mass Index is calculated by dividing a person’s weight by the square of the person’s height (kg/m2).

I will use the scale to determine my weight while I use the tape to measure my height, and then calculate my BMI to get a number. The number I get as my BMI would determine if I am underweight, overweight, or having a normal weight.  

If the number I get is 25.0 or more, it means I am overweight. An ideal BMI that ranges between 18.5 to 24.9 indicates I am healthy.  BMI is mostly used for people between the ages of 18-65 years.

I can also determine the circumference of my waist, and my waist-to-hip ratio using the tape.

that is wrong, its not thymus.