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Finding the Fourth Proportional to 428.37, 642.83 and 211.97

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Solution

The fourth proportional to 428.37, 642.83 and 211.97 is: 318.08

Step by Step Solution

  1. Step 1: Write the proportion equation
    428.37 : 642.83 = 211.97 : x
  2. Step 2: Convert to fraction form
    428.37/642.83 = 211.97/x
  3. Step 3: Cross multiply
    428.37x = 642.83 × 211.97
  4. Step 4: Simplify right side
    428.37x = 136,256.40
  5. Step 5: Solve for x
    x = 136,256.40/428.37
  6. Step 6: Final answer
    x = 318.08

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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.