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Finding the Fourth Proportional to 642.86, 965.88 and 411.85

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Solution

The fourth proportional to 642.86, 965.88 and 411.85 is: 618.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    642.86 : 965.88 = 411.85 : x
  2. Step 2: Convert to fraction form
    642.86/965.88 = 411.85/x
  3. Step 3: Cross multiply
    642.86x = 965.88 × 411.85
  4. Step 4: Simplify right side
    642.86x = 397,797.68
  5. Step 5: Solve for x
    x = 397,797.68/642.86
  6. Step 6: Final answer
    x = 618.79

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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.