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Finding the Fourth Proportional to 665.78, 917.39 and 619.64

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Solution

The fourth proportional to 665.78, 917.39 and 619.64 is: 853.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    665.78 : 917.39 = 619.64 : x
  2. Step 2: Convert to fraction form
    665.78/917.39 = 619.64/x
  3. Step 3: Cross multiply
    665.78x = 917.39 × 619.64
  4. Step 4: Simplify right side
    665.78x = 568,450.73
  5. Step 5: Solve for x
    x = 568,450.73/665.78
  6. Step 6: Final answer
    x = 853.82

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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.