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Finding the Fourth Proportional to 428.27, 642.07 and 212.00

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Solution

The fourth proportional to 428.27, 642.07 and 212.00 is: 317.83

Step by Step Solution

  1. Step 1: Write the proportion equation
    428.27 : 642.07 = 212.00 : x
  2. Step 2: Convert to fraction form
    428.27/642.07 = 212.00/x
  3. Step 3: Cross multiply
    428.27x = 642.07 × 212.00
  4. Step 4: Simplify right side
    428.27x = 136,115.10
  5. Step 5: Solve for x
    x = 136,115.10/428.27
  6. Step 6: Final answer
    x = 317.83

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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.