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Finding the Fourth Proportional to 680.42, 1,019.82 and 391.26

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Solution

The fourth proportional to 680.42, 1,019.82 and 391.26 is: 586.42

Step by Step Solution

  1. Step 1: Write the proportion equation
    680.42 : 1,019.82 = 391.26 : x
  2. Step 2: Convert to fraction form
    680.42/1,019.82 = 391.26/x
  3. Step 3: Cross multiply
    680.42x = 1,019.82 × 391.26
  4. Step 4: Simplify right side
    680.42x = 399,014.77
  5. Step 5: Solve for x
    x = 399,014.77/680.42
  6. Step 6: Final answer
    x = 586.42

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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.