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Finding the Fourth Proportional to 485.92, 729.00 and 139.28

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Solution

The fourth proportional to 485.92, 729.00 and 139.28 is: 208.96

Step by Step Solution

  1. Step 1: Write the proportion equation
    485.92 : 729.00 = 139.28 : x
  2. Step 2: Convert to fraction form
    485.92/729.00 = 139.28/x
  3. Step 3: Cross multiply
    485.92x = 729.00 × 139.28
  4. Step 4: Simplify right side
    485.92x = 101,535.31
  5. Step 5: Solve for x
    x = 101,535.31/485.92
  6. Step 6: Final answer
    x = 208.96

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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.