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Finding the Fourth Proportional to 645.57, 890.60 and 396.90

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Solution

The fourth proportional to 645.57, 890.60 and 396.90 is: 547.54

Step by Step Solution

  1. Step 1: Write the proportion equation
    645.57 : 890.60 = 396.90 : x
  2. Step 2: Convert to fraction form
    645.57/890.60 = 396.90/x
  3. Step 3: Cross multiply
    645.57x = 890.60 × 396.90
  4. Step 4: Simplify right side
    645.57x = 353,477.16
  5. Step 5: Solve for x
    x = 353,477.16/645.57
  6. Step 6: Final answer
    x = 547.54

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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.