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Finding the Fourth Proportional to 136.86, 205.08 and 85.56

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Solution

The fourth proportional to 136.86, 205.08 and 85.56 is: 128.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    136.86 : 205.08 = 85.56 : x
  2. Step 2: Convert to fraction form
    136.86/205.08 = 85.56/x
  3. Step 3: Cross multiply
    136.86x = 205.08 × 85.56
  4. Step 4: Simplify right side
    136.86x = 17,546.64
  5. Step 5: Solve for x
    x = 17,546.64/136.86
  6. Step 6: Final answer
    x = 128.21

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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.