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Finding the Fourth Proportional to 485.59, 669.99 and 289.09

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Solution

The fourth proportional to 485.59, 669.99 and 289.09 is: 398.87

Step by Step Solution

  1. Step 1: Write the proportion equation
    485.59 : 669.99 = 289.09 : x
  2. Step 2: Convert to fraction form
    485.59/669.99 = 289.09/x
  3. Step 3: Cross multiply
    485.59x = 669.99 × 289.09
  4. Step 4: Simplify right side
    485.59x = 193,687.41
  5. Step 5: Solve for x
    x = 193,687.41/485.59
  6. Step 6: Final answer
    x = 398.87

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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.