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Finding the Fourth Proportional to 136.21, 187.91 and 83.72

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Solution

The fourth proportional to 136.21, 187.91 and 83.72 is: 115.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    136.21 : 187.91 = 83.72 : x
  2. Step 2: Convert to fraction form
    136.21/187.91 = 83.72/x
  3. Step 3: Cross multiply
    136.21x = 187.91 × 83.72
  4. Step 4: Simplify right side
    136.21x = 15,731.83
  5. Step 5: Solve for x
    x = 15,731.83/136.21
  6. Step 6: Final answer
    x = 115.50

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.