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Finding the Fourth Proportional to 1,223.07, 1,687.48 and 781.41

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Solution

The fourth proportional to 1,223.07, 1,687.48 and 781.41 is: 1,078.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,223.07 : 1,687.48 = 781.41 : x
  2. Step 2: Convert to fraction form
    1,223.07/1,687.48 = 781.41/x
  3. Step 3: Cross multiply
    1,223.07x = 1,687.48 × 781.41
  4. Step 4: Simplify right side
    1,223.07x = 1,318,613.75
  5. Step 5: Solve for x
    x = 1,318,613.75/1,223.07
  6. Step 6: Final answer
    x = 1,078.12

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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.