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Finding the Fourth Proportional to 780.11, 1,076.42 and 485.27

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Solution

The fourth proportional to 780.11, 1,076.42 and 485.27 is: 669.59

Step by Step Solution

  1. Step 1: Write the proportion equation
    780.11 : 1,076.42 = 485.27 : x
  2. Step 2: Convert to fraction form
    780.11/1,076.42 = 485.27/x
  3. Step 3: Cross multiply
    780.11x = 1,076.42 × 485.27
  4. Step 4: Simplify right side
    780.11x = 522,354.20
  5. Step 5: Solve for x
    x = 522,354.20/780.11
  6. Step 6: Final answer
    x = 669.59

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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.