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Finding the Fourth Proportional to 421.20, 629.28 and 348.48

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Solution

The fourth proportional to 421.20, 629.28 and 348.48 is: 520.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    421.20 : 629.28 = 348.48 : x
  2. Step 2: Convert to fraction form
    421.20/629.28 = 348.48/x
  3. Step 3: Cross multiply
    421.20x = 629.28 × 348.48
  4. Step 4: Simplify right side
    421.20x = 219,291.49
  5. Step 5: Solve for x
    x = 219,291.49/421.20
  6. Step 6: Final answer
    x = 520.64

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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.