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Finding the Fourth Proportional to 680.49, 1,018.62 and 391.05

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Solution

The fourth proportional to 680.49, 1,018.62 and 391.05 is: 585.36

Step by Step Solution

  1. Step 1: Write the proportion equation
    680.49 : 1,018.62 = 391.05 : x
  2. Step 2: Convert to fraction form
    680.49/1,018.62 = 391.05/x
  3. Step 3: Cross multiply
    680.49x = 1,018.62 × 391.05
  4. Step 4: Simplify right side
    680.49x = 398,331.35
  5. Step 5: Solve for x
    x = 398,331.35/680.49
  6. Step 6: Final answer
    x = 585.36

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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.