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Finding the Fourth Proportional to 679.53, 1,020.65 and 660.39

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Solution

The fourth proportional to 679.53, 1,020.65 and 660.39 is: 991.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    679.53 : 1,020.65 = 660.39 : x
  2. Step 2: Convert to fraction form
    679.53/1,020.65 = 660.39/x
  3. Step 3: Cross multiply
    679.53x = 1,020.65 × 660.39
  4. Step 4: Simplify right side
    679.53x = 674,027.05
  5. Step 5: Solve for x
    x = 674,027.05/679.53
  6. Step 6: Final answer
    x = 991.90

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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.