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Finding the Fourth Proportional to 780.86, 1,078.90 and 616.34

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Solution

The fourth proportional to 780.86, 1,078.90 and 616.34 is: 851.58

Step by Step Solution

  1. Step 1: Write the proportion equation
    780.86 : 1,078.90 = 616.34 : x
  2. Step 2: Convert to fraction form
    780.86/1,078.90 = 616.34/x
  3. Step 3: Cross multiply
    780.86x = 1,078.90 × 616.34
  4. Step 4: Simplify right side
    780.86x = 664,970.38
  5. Step 5: Solve for x
    x = 664,970.38/780.86
  6. Step 6: Final answer
    x = 851.58

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.