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Finding the Fourth Proportional to 428.03, 642.04 and 103.40

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Solution

The fourth proportional to 428.03, 642.04 and 103.40 is: 155.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    428.03 : 642.04 = 103.40 : x
  2. Step 2: Convert to fraction form
    428.03/642.04 = 103.40/x
  3. Step 3: Cross multiply
    428.03x = 642.04 × 103.40
  4. Step 4: Simplify right side
    428.03x = 66,383.86
  5. Step 5: Solve for x
    x = 66,383.86/428.03
  6. Step 6: Final answer
    x = 155.09

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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.