The patient has burned his left arm front and back from elbow to fingertips as well as his left chest and abdomen. using the rule of nines, what percentage of his body is burned?

13.5% Let's just add up the areas. Left arm, front and back - 4.5% * 2 = 9% from elbow to fingertips. So only half of the left arm is burned. so 9%/2 = 4.5% Left chest and abdomen. Both the chest and abdomen are 9% each, but only half is burned. So (9+9) / 2 = 9 So the total area burned is 4.5 + 9 = 13.5%