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Finding the Fourth Proportional to 678.44, 938.21 and 666.14

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Solution

The fourth proportional to 678.44, 938.21 and 666.14 is: 921.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    678.44 : 938.21 = 666.14 : x
  2. Step 2: Convert to fraction form
    678.44/938.21 = 666.14/x
  3. Step 3: Cross multiply
    678.44x = 938.21 × 666.14
  4. Step 4: Simplify right side
    678.44x = 624,978.53
  5. Step 5: Solve for x
    x = 624,978.53/678.44
  6. Step 6: Final answer
    x = 921.21

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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.