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Finding the Fourth Proportional to 645.61, 890.99 and 487.96

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Solution

The fourth proportional to 645.61, 890.99 and 487.96 is: 673.42

Step by Step Solution

  1. Step 1: Write the proportion equation
    645.61 : 890.99 = 487.96 : x
  2. Step 2: Convert to fraction form
    645.61/890.99 = 487.96/x
  3. Step 3: Cross multiply
    645.61x = 890.99 × 487.96
  4. Step 4: Simplify right side
    645.61x = 434,767.48
  5. Step 5: Solve for x
    x = 434,767.48/645.61
  6. Step 6: Final answer
    x = 673.42

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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.