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Finding the Fourth Proportional to 780.78, 1,076.28 and 518.64

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Solution

The fourth proportional to 780.78, 1,076.28 and 518.64 is: 714.93

Step by Step Solution

  1. Step 1: Write the proportion equation
    780.78 : 1,076.28 = 518.64 : x
  2. Step 2: Convert to fraction form
    780.78/1,076.28 = 518.64/x
  3. Step 3: Cross multiply
    780.78x = 1,076.28 × 518.64
  4. Step 4: Simplify right side
    780.78x = 558,201.86
  5. Step 5: Solve for x
    x = 558,201.86/780.78
  6. Step 6: Final answer
    x = 714.93

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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.