Finding the Fourth Proportional to 152.56, 210.48 and 100.72

Step by Step Solution

1. Step 1: Write the proportion equation
   152.56 : 210.48 = 100.72 : x
2. Step 2: Convert to fraction form
   152.56/210.48 = 100.72/x
3. Step 3: Cross multiply
   152.56x = 210.48 × 100.72
4. Step 4: Simplify right side
   152.56x = 21,199.55
5. Step 5: Solve for x
   x = 21,199.55/152.56
6. Step 6: Final answer
   x = 138.96