The human body is often drawn using specific ratios. The average height of an adult is drawn using seven head lengths ( the height of the head is 1/7 the total height). If a person in a painting is 63 centimeters tall, how tall is the person’s head

To do this just multiply 63cm by 1/7 this is equivalent to dividing it by seven which I personally think is easier. 63/7=9
Your answer is 9 cm.