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Finding the Fourth Proportional to 681.18, 1,020.15 and 391.74

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Solution

The fourth proportional to 681.18, 1,020.15 and 391.74 is: 586.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    681.18 : 1,020.15 = 391.74 : x
  2. Step 2: Convert to fraction form
    681.18/1,020.15 = 391.74/x
  3. Step 3: Cross multiply
    681.18x = 1,020.15 × 391.74
  4. Step 4: Simplify right side
    681.18x = 399,633.56
  5. Step 5: Solve for x
    x = 399,633.56/681.18
  6. Step 6: Final answer
    x = 586.68

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.