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Finding the Fourth Proportional to 413.80, 620.46 and 139.72

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Solution

The fourth proportional to 413.80, 620.46 and 139.72 is: 209.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    413.80 : 620.46 = 139.72 : x
  2. Step 2: Convert to fraction form
    413.80/620.46 = 139.72/x
  3. Step 3: Cross multiply
    413.80x = 620.46 × 139.72
  4. Step 4: Simplify right side
    413.80x = 86,690.67
  5. Step 5: Solve for x
    x = 86,690.67/413.80
  6. Step 6: Final answer
    x = 209.50

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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.