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Finding the Fourth Proportional to 420.12, 579.78 and 243.09

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Solution

The fourth proportional to 420.12, 579.78 and 243.09 is: 335.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.12 : 579.78 = 243.09 : x
  2. Step 2: Convert to fraction form
    420.12/579.78 = 243.09/x
  3. Step 3: Cross multiply
    420.12x = 579.78 × 243.09
  4. Step 4: Simplify right side
    420.12x = 140,938.72
  5. Step 5: Solve for x
    x = 140,938.72/420.12
  6. Step 6: Final answer
    x = 335.47

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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.