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Finding the Fourth Proportional to 645.13, 890.55 and 396.55

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Solution

The fourth proportional to 645.13, 890.55 and 396.55 is: 547.41

Step by Step Solution

  1. Step 1: Write the proportion equation
    645.13 : 890.55 = 396.55 : x
  2. Step 2: Convert to fraction form
    645.13/890.55 = 396.55/x
  3. Step 3: Cross multiply
    645.13x = 890.55 × 396.55
  4. Step 4: Simplify right side
    645.13x = 353,147.60
  5. Step 5: Solve for x
    x = 353,147.60/645.13
  6. Step 6: Final answer
    x = 547.41

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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.