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Finding the Fourth Proportional to 902.70, 1,245.78 and 641.88

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Solution

The fourth proportional to 902.70, 1,245.78 and 641.88 is: 885.83

Step by Step Solution

  1. Step 1: Write the proportion equation
    902.70 : 1,245.78 = 641.88 : x
  2. Step 2: Convert to fraction form
    902.70/1,245.78 = 641.88/x
  3. Step 3: Cross multiply
    902.70x = 1,245.78 × 641.88
  4. Step 4: Simplify right side
    902.70x = 799,641.27
  5. Step 5: Solve for x
    x = 799,641.27/902.70
  6. Step 6: Final answer
    x = 885.83

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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.