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Finding the Fourth Proportional to 285.78, 391.68 and 285.30

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Solution

The fourth proportional to 285.78, 391.68 and 285.30 is: 391.02

Step by Step Solution

  1. Step 1: Write the proportion equation
    285.78 : 391.68 = 285.30 : x
  2. Step 2: Convert to fraction form
    285.78/391.68 = 285.30/x
  3. Step 3: Cross multiply
    285.78x = 391.68 × 285.30
  4. Step 4: Simplify right side
    285.78x = 111,746.30
  5. Step 5: Solve for x
    x = 111,746.30/285.78
  6. Step 6: Final answer
    x = 391.02

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Why These Related Problems?

These problems maintain the same ratio (1.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.