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Finding the Fourth Proportional to 428.06, 642 and 154.15

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Solution

The fourth proportional to 428.06, 642 and 154.15 is: 231.19

Step by Step Solution

  1. Step 1: Write the proportion equation
    428.06 : 642 = 154.15 : x
  2. Step 2: Convert to fraction form
    428.06/642 = 154.15/x
  3. Step 3: Cross multiply
    428.06x = 642 × 154.15
  4. Step 4: Simplify right side
    428.06x = 98,964.30
  5. Step 5: Solve for x
    x = 98,964.30/428.06
  6. Step 6: Final answer
    x = 231.19

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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.