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Finding the Fourth Proportional to 103.64, 155.28 and 85.38

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Solution

The fourth proportional to 103.64, 155.28 and 85.38 is: 127.92

Step by Step Solution

  1. Step 1: Write the proportion equation
    103.64 : 155.28 = 85.38 : x
  2. Step 2: Convert to fraction form
    103.64/155.28 = 85.38/x
  3. Step 3: Cross multiply
    103.64x = 155.28 × 85.38
  4. Step 4: Simplify right side
    103.64x = 13,257.81
  5. Step 5: Solve for x
    x = 13,257.81/103.64
  6. Step 6: Final answer
    x = 127.92

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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.