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Finding the Fourth Proportional to 136.09, 188.69 and 128.80

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Solution

The fourth proportional to 136.09, 188.69 and 128.80 is: 178.58

Step by Step Solution

  1. Step 1: Write the proportion equation
    136.09 : 188.69 = 128.80 : x
  2. Step 2: Convert to fraction form
    136.09/188.69 = 128.80/x
  3. Step 3: Cross multiply
    136.09x = 188.69 × 128.80
  4. Step 4: Simplify right side
    136.09x = 24,303.27
  5. Step 5: Solve for x
    x = 24,303.27/136.09
  6. Step 6: Final answer
    x = 178.58

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Why These Related Problems?

These problems maintain the same ratio (1.39) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.