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Finding the Fourth Proportional to 781.38, 1,078.19 and 663.82

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Solution

The fourth proportional to 781.38, 1,078.19 and 663.82 is: 915.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    781.38 : 1,078.19 = 663.82 : x
  2. Step 2: Convert to fraction form
    781.38/1,078.19 = 663.82/x
  3. Step 3: Cross multiply
    781.38x = 1,078.19 × 663.82
  4. Step 4: Simplify right side
    781.38x = 715,720.77
  5. Step 5: Solve for x
    x = 715,720.77/781.38
  6. Step 6: Final answer
    x = 915.98

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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.