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Finding the Fourth Proportional to 679.18, 1,017.15 and 389.74

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Solution

The fourth proportional to 679.18, 1,017.15 and 389.74 is: 583.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    679.18 : 1,017.15 = 389.74 : x
  2. Step 2: Convert to fraction form
    679.18/1,017.15 = 389.74/x
  3. Step 3: Cross multiply
    679.18x = 1,017.15 × 389.74
  4. Step 4: Simplify right side
    679.18x = 396,424.04
  5. Step 5: Solve for x
    x = 396,424.04/679.18
  6. Step 6: Final answer
    x = 583.68

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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.