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Finding the Fourth Proportional to 780.34, 1,076.78 and 518.44

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Solution

The fourth proportional to 780.34, 1,076.78 and 518.44 is: 715.39

Step by Step Solution

  1. Step 1: Write the proportion equation
    780.34 : 1,076.78 = 518.44 : x
  2. Step 2: Convert to fraction form
    780.34/1,076.78 = 518.44/x
  3. Step 3: Cross multiply
    780.34x = 1,076.78 × 518.44
  4. Step 4: Simplify right side
    780.34x = 558,245.82
  5. Step 5: Solve for x
    x = 558,245.82/780.34
  6. Step 6: Final answer
    x = 715.39

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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.