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Finding the Fourth Proportional to 781.68, 1,078.38 and 471

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Solution

The fourth proportional to 781.68, 1,078.38 and 471 is: 649.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    781.68 : 1,078.38 = 471 : x
  2. Step 2: Convert to fraction form
    781.68/1,078.38 = 471/x
  3. Step 3: Cross multiply
    781.68x = 1,078.38 × 471
  4. Step 4: Simplify right side
    781.68x = 507,916.98
  5. Step 5: Solve for x
    x = 507,916.98/781.68
  6. Step 6: Final answer
    x = 649.78

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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.