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Finding the Fourth Proportional to 645.62, 890.90 and 396.88

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Solution

The fourth proportional to 645.62, 890.90 and 396.88 is: 547.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    645.62 : 890.90 = 396.88 : x
  2. Step 2: Convert to fraction form
    645.62/890.90 = 396.88/x
  3. Step 3: Cross multiply
    645.62x = 890.90 × 396.88
  4. Step 4: Simplify right side
    645.62x = 353,577.67
  5. Step 5: Solve for x
    x = 353,577.67/645.62
  6. Step 6: Final answer
    x = 547.66

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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.