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Finding the Fourth Proportional to 645.22, 890.08 and 408.78

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Solution

The fourth proportional to 645.22, 890.08 and 408.78 is: 563.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    645.22 : 890.08 = 408.78 : x
  2. Step 2: Convert to fraction form
    645.22/890.08 = 408.78/x
  3. Step 3: Cross multiply
    645.22x = 890.08 × 408.78
  4. Step 4: Simplify right side
    645.22x = 363,841.43
  5. Step 5: Solve for x
    x = 363,841.43/645.22
  6. Step 6: Final answer
    x = 563.90

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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.