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Finding the Fourth Proportional to 1,278.88, 1,765.02 and 781.42

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Solution

The fourth proportional to 1,278.88, 1,765.02 and 781.42 is: 1,078.46

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,278.88 : 1,765.02 = 781.42 : x
  2. Step 2: Convert to fraction form
    1,278.88/1,765.02 = 781.42/x
  3. Step 3: Cross multiply
    1,278.88x = 1,765.02 × 781.42
  4. Step 4: Simplify right side
    1,278.88x = 1,379,221.93
  5. Step 5: Solve for x
    x = 1,379,221.93/1,278.88
  6. Step 6: Final answer
    x = 1,078.46

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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.