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Finding the Fourth Proportional to 679.77, 1,019.61 and 391.77

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Solution

The fourth proportional to 679.77, 1,019.61 and 391.77 is: 587.63

Step by Step Solution

  1. Step 1: Write the proportion equation
    679.77 : 1,019.61 = 391.77 : x
  2. Step 2: Convert to fraction form
    679.77/1,019.61 = 391.77/x
  3. Step 3: Cross multiply
    679.77x = 1,019.61 × 391.77
  4. Step 4: Simplify right side
    679.77x = 399,452.61
  5. Step 5: Solve for x
    x = 399,452.61/679.77
  6. Step 6: Final answer
    x = 587.63

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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.