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Finding the Fourth Proportional to 1,253.79, 1,729.89 and 781.50

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Solution

The fourth proportional to 1,253.79, 1,729.89 and 781.50 is: 1,078.26

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,253.79 : 1,729.89 = 781.50 : x
  2. Step 2: Convert to fraction form
    1,253.79/1,729.89 = 781.50/x
  3. Step 3: Cross multiply
    1,253.79x = 1,729.89 × 781.50
  4. Step 4: Simplify right side
    1,253.79x = 1,351,909.04
  5. Step 5: Solve for x
    x = 1,351,909.04/1,253.79
  6. Step 6: Final answer
    x = 1,078.26

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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.