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Finding the Fourth Proportional to 420.89, 630.86 and 339.80

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Solution

The fourth proportional to 420.89, 630.86 and 339.80 is: 509.31

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.89 : 630.86 = 339.80 : x
  2. Step 2: Convert to fraction form
    420.89/630.86 = 339.80/x
  3. Step 3: Cross multiply
    420.89x = 630.86 × 339.80
  4. Step 4: Simplify right side
    420.89x = 214,361.37
  5. Step 5: Solve for x
    x = 214,361.37/420.89
  6. Step 6: Final answer
    x = 509.31

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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.