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Finding the Fourth Proportional to 679.30, 1,017.66 and 390.12

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Solution

The fourth proportional to 679.30, 1,017.66 and 390.12 is: 584.44

Step by Step Solution

  1. Step 1: Write the proportion equation
    679.30 : 1,017.66 = 390.12 : x
  2. Step 2: Convert to fraction form
    679.30/1,017.66 = 390.12/x
  3. Step 3: Cross multiply
    679.30x = 1,017.66 × 390.12
  4. Step 4: Simplify right side
    679.30x = 397,009.52
  5. Step 5: Solve for x
    x = 397,009.52/679.30
  6. Step 6: Final answer
    x = 584.44

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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.