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Finding the Fourth Proportional to 486.60, 729.86 and 139.92

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Solution

The fourth proportional to 486.60, 729.86 and 139.92 is: 209.87

Step by Step Solution

  1. Step 1: Write the proportion equation
    486.60 : 729.86 = 139.92 : x
  2. Step 2: Convert to fraction form
    486.60/729.86 = 139.92/x
  3. Step 3: Cross multiply
    486.60x = 729.86 × 139.92
  4. Step 4: Simplify right side
    486.60x = 102,122.01
  5. Step 5: Solve for x
    x = 102,122.01/486.60
  6. Step 6: Final answer
    x = 209.87

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.