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Finding the Fourth Proportional to 681.09, 939.92 and 386.40

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Solution

The fourth proportional to 681.09, 939.92 and 386.40 is: 533.24

Step by Step Solution

  1. Step 1: Write the proportion equation
    681.09 : 939.92 = 386.40 : x
  2. Step 2: Convert to fraction form
    681.09/939.92 = 386.40/x
  3. Step 3: Cross multiply
    681.09x = 939.92 × 386.40
  4. Step 4: Simplify right side
    681.09x = 363,185.09
  5. Step 5: Solve for x
    x = 363,185.09/681.09
  6. Step 6: Final answer
    x = 533.24

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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.