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Finding the Fourth Proportional to 421.20, 580.80 and 349.20

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Solution

The fourth proportional to 421.20, 580.80 and 349.20 is: 481.52

Step by Step Solution

  1. Step 1: Write the proportion equation
    421.20 : 580.80 = 349.20 : x
  2. Step 2: Convert to fraction form
    421.20/580.80 = 349.20/x
  3. Step 3: Cross multiply
    421.20x = 580.80 × 349.20
  4. Step 4: Simplify right side
    421.20x = 202,815.36
  5. Step 5: Solve for x
    x = 202,815.36/421.20
  6. Step 6: Final answer
    x = 481.52

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.