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Finding the Fourth Proportional to 980.61, 1,353.32 and 644.73

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Solution

The fourth proportional to 980.61, 1,353.32 and 644.73 is: 889.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    980.61 : 1,353.32 = 644.73 : x
  2. Step 2: Convert to fraction form
    980.61/1,353.32 = 644.73/x
  3. Step 3: Cross multiply
    980.61x = 1,353.32 × 644.73
  4. Step 4: Simplify right side
    980.61x = 872,522.78
  5. Step 5: Solve for x
    x = 872,522.78/980.61
  6. Step 6: Final answer
    x = 889.78

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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.