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Finding the Fourth Proportional to 781.18, 1,078.02 and 486.42

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Solution

The fourth proportional to 781.18, 1,078.02 and 486.42 is: 671.25

Step by Step Solution

  1. Step 1: Write the proportion equation
    781.18 : 1,078.02 = 486.42 : x
  2. Step 2: Convert to fraction form
    781.18/1,078.02 = 486.42/x
  3. Step 3: Cross multiply
    781.18x = 1,078.02 × 486.42
  4. Step 4: Simplify right side
    781.18x = 524,370.49
  5. Step 5: Solve for x
    x = 524,370.49/781.18
  6. Step 6: Final answer
    x = 671.25

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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.