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Finding the Fourth Proportional to 1,279.40, 1,919.10 and 413.72

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Solution

The fourth proportional to 1,279.40, 1,919.10 and 413.72 is: 620.58

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,279.40 : 1,919.10 = 413.72 : x
  2. Step 2: Convert to fraction form
    1,279.40/1,919.10 = 413.72/x
  3. Step 3: Cross multiply
    1,279.40x = 1,919.10 × 413.72
  4. Step 4: Simplify right side
    1,279.40x = 793,970.05
  5. Step 5: Solve for x
    x = 793,970.05/1,279.40
  6. Step 6: Final answer
    x = 620.58

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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.