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Finding the Fourth Proportional to 681.12, 939.90 and 401.40

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Solution

The fourth proportional to 681.12, 939.90 and 401.40 is: 553.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    681.12 : 939.90 = 401.40 : x
  2. Step 2: Convert to fraction form
    681.12/939.90 = 401.40/x
  3. Step 3: Cross multiply
    681.12x = 939.90 × 401.40
  4. Step 4: Simplify right side
    681.12x = 377,275.86
  5. Step 5: Solve for x
    x = 377,275.86/681.12
  6. Step 6: Final answer
    x = 553.91

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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.