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Finding the Fourth Proportional to 425.86, 641.86 and 421.74

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Solution

The fourth proportional to 425.86, 641.86 and 421.74 is: 635.65

Step by Step Solution

  1. Step 1: Write the proportion equation
    425.86 : 641.86 = 421.74 : x
  2. Step 2: Convert to fraction form
    425.86/641.86 = 421.74/x
  3. Step 3: Cross multiply
    425.86x = 641.86 × 421.74
  4. Step 4: Simplify right side
    425.86x = 270,696.98
  5. Step 5: Solve for x
    x = 270,696.98/425.86
  6. Step 6: Final answer
    x = 635.65

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.