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Finding the Fourth Proportional to 720.37, 1,078.54 and 390.12

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Solution

The fourth proportional to 720.37, 1,078.54 and 390.12 is: 584.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    720.37 : 1,078.54 = 390.12 : x
  2. Step 2: Convert to fraction form
    720.37/1,078.54 = 390.12/x
  3. Step 3: Cross multiply
    720.37x = 1,078.54 × 390.12
  4. Step 4: Simplify right side
    720.37x = 420,761.75
  5. Step 5: Solve for x
    x = 420,761.75/720.37
  6. Step 6: Final answer
    x = 584.09

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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.