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Finding the Fourth Proportional to 681, 939.78 and 386.28

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Solution

The fourth proportional to 681, 939.78 and 386.28 is: 533.07

Step by Step Solution

  1. Step 1: Write the proportion equation
    681 : 939.78 = 386.28 : x
  2. Step 2: Convert to fraction form
    681/939.78 = 386.28/x
  3. Step 3: Cross multiply
    681x = 939.78 × 386.28
  4. Step 4: Simplify right side
    681x = 363,018.22
  5. Step 5: Solve for x
    x = 363,018.22/681
  6. Step 6: Final answer
    x = 533.07

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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.