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Finding the Fourth Proportional to 486.64, 729.85 and 139.90

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Solution

The fourth proportional to 486.64, 729.85 and 139.90 is: 209.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    486.64 : 729.85 = 139.90 : x
  2. Step 2: Convert to fraction form
    486.64/729.85 = 139.90/x
  3. Step 3: Cross multiply
    486.64x = 729.85 × 139.90
  4. Step 4: Simplify right side
    486.64x = 102,103.15
  5. Step 5: Solve for x
    x = 102,103.15/486.64
  6. Step 6: Final answer
    x = 209.81

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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.