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Finding the Fourth Proportional to 780.48, 1,076.02 and 647.20

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Solution

The fourth proportional to 780.48, 1,076.02 and 647.20 is: 892.27

Step by Step Solution

  1. Step 1: Write the proportion equation
    780.48 : 1,076.02 = 647.20 : x
  2. Step 2: Convert to fraction form
    780.48/1,076.02 = 647.20/x
  3. Step 3: Cross multiply
    780.48x = 1,076.02 × 647.20
  4. Step 4: Simplify right side
    780.48x = 696,400.14
  5. Step 5: Solve for x
    x = 696,400.14/780.48
  6. Step 6: Final answer
    x = 892.27

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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.