Answer:
4.5. inches
Step-by-step explanation:
Given that:
Thickness of first book = 2 1/4 inches
Thickness of second book = same as first = 2 1/4 Inches
Stacking both books together, height of stack will be :
2 1/4 inches * 2
Height of stack = 9/4 * 2
Height of stack = 18 /4 = 4.5 inches
