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Finding the Fourth Proportional to 780.78, 1,077.54 and 486.09

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Solution

The fourth proportional to 780.78, 1,077.54 and 486.09 is: 670.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    780.78 : 1,077.54 = 486.09 : x
  2. Step 2: Convert to fraction form
    780.78/1,077.54 = 486.09/x
  3. Step 3: Cross multiply
    780.78x = 1,077.54 × 486.09
  4. Step 4: Simplify right side
    780.78x = 523,784.68
  5. Step 5: Solve for x
    x = 523,784.68/780.78
  6. Step 6: Final answer
    x = 670.85

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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.