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Finding the Fourth Proportional to 428.22, 642.02 and 135.59

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Solution

The fourth proportional to 428.22, 642.02 and 135.59 is: 203.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    428.22 : 642.02 = 135.59 : x
  2. Step 2: Convert to fraction form
    428.22/642.02 = 135.59/x
  3. Step 3: Cross multiply
    428.22x = 642.02 × 135.59
  4. Step 4: Simplify right side
    428.22x = 87,047.60
  5. Step 5: Solve for x
    x = 87,047.60/428.22
  6. Step 6: Final answer
    x = 203.28

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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.