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Finding the Fourth Proportional to 679.78, 1,021.04 and 660.64

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Solution

The fourth proportional to 679.78, 1,021.04 and 660.64 is: 992.29

Step by Step Solution

  1. Step 1: Write the proportion equation
    679.78 : 1,021.04 = 660.64 : x
  2. Step 2: Convert to fraction form
    679.78/1,021.04 = 660.64/x
  3. Step 3: Cross multiply
    679.78x = 1,021.04 × 660.64
  4. Step 4: Simplify right side
    679.78x = 674,539.87
  5. Step 5: Solve for x
    x = 674,539.87/679.78
  6. Step 6: Final answer
    x = 992.29

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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.