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Finding the Fourth Proportional to 428.18, 642.27 and 103.55

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Solution

The fourth proportional to 428.18, 642.27 and 103.55 is: 155.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    428.18 : 642.27 = 103.55 : x
  2. Step 2: Convert to fraction form
    428.18/642.27 = 103.55/x
  3. Step 3: Cross multiply
    428.18x = 642.27 × 103.55
  4. Step 4: Simplify right side
    428.18x = 66,505.44
  5. Step 5: Solve for x
    x = 66,505.44/428.18
  6. Step 6: Final answer
    x = 155.32

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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.