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Finding the Fourth Proportional to 680.67, 1,021.01 and 391.77

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Solution

The fourth proportional to 680.67, 1,021.01 and 391.77 is: 587.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    680.67 : 1,021.01 = 391.77 : x
  2. Step 2: Convert to fraction form
    680.67/1,021.01 = 391.77/x
  3. Step 3: Cross multiply
    680.67x = 1,021.01 × 391.77
  4. Step 4: Simplify right side
    680.67x = 399,999.13
  5. Step 5: Solve for x
    x = 399,999.13/680.67
  6. Step 6: Final answer
    x = 587.66

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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.