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Finding the Fourth Proportional to 319.61, 479.61 and 285.78

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Solution

The fourth proportional to 319.61, 479.61 and 285.78 is: 428.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    319.61 : 479.61 = 285.78 : x
  2. Step 2: Convert to fraction form
    319.61/479.61 = 285.78/x
  3. Step 3: Cross multiply
    319.61x = 479.61 × 285.78
  4. Step 4: Simplify right side
    319.61x = 137,062.95
  5. Step 5: Solve for x
    x = 137,062.95/319.61
  6. Step 6: Final answer
    x = 428.85

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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.