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Finding the Fourth Proportional to 1,379.25, 1,903.34 and 781.74

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Solution

The fourth proportional to 1,379.25, 1,903.34 and 781.74 is: 1,078.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,379.25 : 1,903.34 = 781.74 : x
  2. Step 2: Convert to fraction form
    1,379.25/1,903.34 = 781.74/x
  3. Step 3: Cross multiply
    1,379.25x = 1,903.34 × 781.74
  4. Step 4: Simplify right side
    1,379.25x = 1,487,917.01
  5. Step 5: Solve for x
    x = 1,487,917.01/1,379.25
  6. Step 6: Final answer
    x = 1,078.79

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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.