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Finding the Fourth Proportional to 389.67, 585.99 and 311.78

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Solution

The fourth proportional to 389.67, 585.99 and 311.78 is: 468.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    389.67 : 585.99 = 311.78 : x
  2. Step 2: Convert to fraction form
    389.67/585.99 = 311.78/x
  3. Step 3: Cross multiply
    389.67x = 585.99 × 311.78
  4. Step 4: Simplify right side
    389.67x = 182,697.03
  5. Step 5: Solve for x
    x = 182,697.03/389.67
  6. Step 6: Final answer
    x = 468.85

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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.