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Finding the Fourth Proportional to 139.56, 192.48 and 87.72

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Solution

The fourth proportional to 139.56, 192.48 and 87.72 is: 120.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    139.56 : 192.48 = 87.72 : x
  2. Step 2: Convert to fraction form
    139.56/192.48 = 87.72/x
  3. Step 3: Cross multiply
    139.56x = 192.48 × 87.72
  4. Step 4: Simplify right side
    139.56x = 16,884.35
  5. Step 5: Solve for x
    x = 16,884.35/139.56
  6. Step 6: Final answer
    x = 120.98

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.