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Finding the Fourth Proportional to 355.05, 489.65 and 311.31

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Solution

The fourth proportional to 355.05, 489.65 and 311.31 is: 429.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    355.05 : 489.65 = 311.31 : x
  2. Step 2: Convert to fraction form
    355.05/489.65 = 311.31/x
  3. Step 3: Cross multiply
    355.05x = 489.65 × 311.31
  4. Step 4: Simplify right side
    355.05x = 152,431.38
  5. Step 5: Solve for x
    x = 152,431.38/355.05
  6. Step 6: Final answer
    x = 429.32

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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.