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Finding the Fourth Proportional to 428.55, 641.80 and 418.22

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Solution

The fourth proportional to 428.55, 641.80 and 418.22 is: 626.33

Step by Step Solution

  1. Step 1: Write the proportion equation
    428.55 : 641.80 = 418.22 : x
  2. Step 2: Convert to fraction form
    428.55/641.80 = 418.22/x
  3. Step 3: Cross multiply
    428.55x = 641.80 × 418.22
  4. Step 4: Simplify right side
    428.55x = 268,413.60
  5. Step 5: Solve for x
    x = 268,413.60/428.55
  6. Step 6: Final answer
    x = 626.33

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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.