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Finding the Fourth Proportional to 1,189.55, 1,781.39 and 778.28

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Solution

The fourth proportional to 1,189.55, 1,781.39 and 778.28 is: 1,165.49

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,189.55 : 1,781.39 = 778.28 : x
  2. Step 2: Convert to fraction form
    1,189.55/1,781.39 = 778.28/x
  3. Step 3: Cross multiply
    1,189.55x = 1,781.39 × 778.28
  4. Step 4: Simplify right side
    1,189.55x = 1,386,413.25
  5. Step 5: Solve for x
    x = 1,386,413.25/1,189.55
  6. Step 6: Final answer
    x = 1,165.49

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.