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Finding the Fourth Proportional to 98.72, 136.28 and 76.85

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Solution

The fourth proportional to 98.72, 136.28 and 76.85 is: 106.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    98.72 : 136.28 = 76.85 : x
  2. Step 2: Convert to fraction form
    98.72/136.28 = 76.85/x
  3. Step 3: Cross multiply
    98.72x = 136.28 × 76.85
  4. Step 4: Simplify right side
    98.72x = 10,473.14
  5. Step 5: Solve for x
    x = 10,473.14/98.72
  6. Step 6: Final answer
    x = 106.09

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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.