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Finding the Fourth Proportional to 680.39, 938.21 and 665.34

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Solution

The fourth proportional to 680.39, 938.21 and 665.34 is: 917.46

Step by Step Solution

  1. Step 1: Write the proportion equation
    680.39 : 938.21 = 665.34 : x
  2. Step 2: Convert to fraction form
    680.39/938.21 = 665.34/x
  3. Step 3: Cross multiply
    680.39x = 938.21 × 665.34
  4. Step 4: Simplify right side
    680.39x = 624,228.64
  5. Step 5: Solve for x
    x = 624,228.64/680.39
  6. Step 6: Final answer
    x = 917.46

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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.