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Finding the Fourth Proportional to 420.05, 579.66 and 231

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Solution

The fourth proportional to 420.05, 579.66 and 231 is: 318.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.05 : 579.66 = 231 : x
  2. Step 2: Convert to fraction form
    420.05/579.66 = 231/x
  3. Step 3: Cross multiply
    420.05x = 579.66 × 231
  4. Step 4: Simplify right side
    420.05x = 133,901.46
  5. Step 5: Solve for x
    x = 133,901.46/420.05
  6. Step 6: Final answer
    x = 318.78

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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.