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Finding the Fourth Proportional to 428.66, 642.61 and 206.18

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Solution

The fourth proportional to 428.66, 642.61 and 206.18 is: 309.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    428.66 : 642.61 = 206.18 : x
  2. Step 2: Convert to fraction form
    428.66/642.61 = 206.18/x
  3. Step 3: Cross multiply
    428.66x = 642.61 × 206.18
  4. Step 4: Simplify right side
    428.66x = 132,491.72
  5. Step 5: Solve for x
    x = 132,491.72/428.66
  6. Step 6: Final answer
    x = 309.09

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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.