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Finding the Fourth Proportional to 103.39, 155.15 and 85.57

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Solution

The fourth proportional to 103.39, 155.15 and 85.57 is: 128.41

Step by Step Solution

  1. Step 1: Write the proportion equation
    103.39 : 155.15 = 85.57 : x
  2. Step 2: Convert to fraction form
    103.39/155.15 = 85.57/x
  3. Step 3: Cross multiply
    103.39x = 155.15 × 85.57
  4. Step 4: Simplify right side
    103.39x = 13,276.19
  5. Step 5: Solve for x
    x = 13,276.19/103.39
  6. Step 6: Final answer
    x = 128.41

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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.