Final answer:
The demand relationship where percentage changes in quantity demanded and price are equal in absolute value is called unitary elastic demand.
Step-by-step explanation:
The demand relationship in which the percentage change in quantity of a product demanded is the same as the percentage change in price in absolute value is known as unitary elastic demand. This means that if the price of a product increases by a certain percentage, the quantity demanded of that product will decrease by the same percentage, and vice versa.
For example, a 5% increase in price would result in a 5% decrease in quantity demanded. Price elasticity of demand is the concept that measures this responsiveness of the quantity demanded to a change in price.