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Finding the Fourth Proportional to 485.40, 729.90 and 406.20

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Solution

The fourth proportional to 485.40, 729.90 and 406.20 is: 610.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    485.40 : 729.90 = 406.20 : x
  2. Step 2: Convert to fraction form
    485.40/729.90 = 406.20/x
  3. Step 3: Cross multiply
    485.40x = 729.90 × 406.20
  4. Step 4: Simplify right side
    485.40x = 296,485.38
  5. Step 5: Solve for x
    x = 296,485.38/485.40
  6. Step 6: Final answer
    x = 610.81

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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.