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Finding the Fourth Proportional to 645.35, 890.25 and 408.90

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Solution

The fourth proportional to 645.35, 890.25 and 408.90 is: 564.07

Step by Step Solution

  1. Step 1: Write the proportion equation
    645.35 : 890.25 = 408.90 : x
  2. Step 2: Convert to fraction form
    645.35/890.25 = 408.90/x
  3. Step 3: Cross multiply
    645.35x = 890.25 × 408.90
  4. Step 4: Simplify right side
    645.35x = 364,019.89
  5. Step 5: Solve for x
    x = 364,019.89/645.35
  6. Step 6: Final answer
    x = 564.07

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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.