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Finding the Fourth Proportional to 655.09, 981.39 and 391

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Solution

The fourth proportional to 655.09, 981.39 and 391 is: 585.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    655.09 : 981.39 = 391 : x
  2. Step 2: Convert to fraction form
    655.09/981.39 = 391/x
  3. Step 3: Cross multiply
    655.09x = 981.39 × 391
  4. Step 4: Simplify right side
    655.09x = 383,723.49
  5. Step 5: Solve for x
    x = 383,723.49/655.09
  6. Step 6: Final answer
    x = 585.76

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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.