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Finding the Fourth Proportional to 421.62, 629.70 and 418.86

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Solution

The fourth proportional to 421.62, 629.70 and 418.86 is: 625.58

Step by Step Solution

  1. Step 1: Write the proportion equation
    421.62 : 629.70 = 418.86 : x
  2. Step 2: Convert to fraction form
    421.62/629.70 = 418.86/x
  3. Step 3: Cross multiply
    421.62x = 629.70 × 418.86
  4. Step 4: Simplify right side
    421.62x = 263,756.14
  5. Step 5: Solve for x
    x = 263,756.14/421.62
  6. Step 6: Final answer
    x = 625.58

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.