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Finding the Fourth Proportional to 644.60, 966.90 and 640.55

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Solution

The fourth proportional to 644.60, 966.90 and 640.55 is: 960.83

Step by Step Solution

  1. Step 1: Write the proportion equation
    644.60 : 966.90 = 640.55 : x
  2. Step 2: Convert to fraction form
    644.60/966.90 = 640.55/x
  3. Step 3: Cross multiply
    644.60x = 966.90 × 640.55
  4. Step 4: Simplify right side
    644.60x = 619,347.80
  5. Step 5: Solve for x
    x = 619,347.80/644.60
  6. Step 6: Final answer
    x = 960.83

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.