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Finding the Fourth Proportional to 425.40, 638.16 and 136.84

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Solution

The fourth proportional to 425.40, 638.16 and 136.84 is: 205.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    425.40 : 638.16 = 136.84 : x
  2. Step 2: Convert to fraction form
    425.40/638.16 = 136.84/x
  3. Step 3: Cross multiply
    425.40x = 638.16 × 136.84
  4. Step 4: Simplify right side
    425.40x = 87,325.81
  5. Step 5: Solve for x
    x = 87,325.81/425.40
  6. Step 6: Final answer
    x = 205.28

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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.