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Finding the Fourth Proportional to 645.87, 891.09 and 397.11

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Solution

The fourth proportional to 645.87, 891.09 and 397.11 is: 547.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    645.87 : 891.09 = 397.11 : x
  2. Step 2: Convert to fraction form
    645.87/891.09 = 397.11/x
  3. Step 3: Cross multiply
    645.87x = 891.09 × 397.11
  4. Step 4: Simplify right side
    645.87x = 353,860.75
  5. Step 5: Solve for x
    x = 353,860.75/645.87
  6. Step 6: Final answer
    x = 547.88

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.