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Finding the Fourth Proportional to 356.18, 489.96 and 311.72

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Solution

The fourth proportional to 356.18, 489.96 and 311.72 is: 428.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    356.18 : 489.96 = 311.72 : x
  2. Step 2: Convert to fraction form
    356.18/489.96 = 311.72/x
  3. Step 3: Cross multiply
    356.18x = 489.96 × 311.72
  4. Step 4: Simplify right side
    356.18x = 152,730.33
  5. Step 5: Solve for x
    x = 152,730.33/356.18
  6. Step 6: Final answer
    x = 428.80

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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.