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Finding the Fourth Proportional to 679.20, 1,017.16 and 390.08

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Solution

The fourth proportional to 679.20, 1,017.16 and 390.08 is: 584.18

Step by Step Solution

  1. Step 1: Write the proportion equation
    679.20 : 1,017.16 = 390.08 : x
  2. Step 2: Convert to fraction form
    679.20/1,017.16 = 390.08/x
  3. Step 3: Cross multiply
    679.20x = 1,017.16 × 390.08
  4. Step 4: Simplify right side
    679.20x = 396,773.77
  5. Step 5: Solve for x
    x = 396,773.77/679.20
  6. Step 6: Final answer
    x = 584.18

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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.