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Finding the Fourth Proportional to 98.90, 136.56 and 72.81

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Solution

The fourth proportional to 98.90, 136.56 and 72.81 is: 100.54

Step by Step Solution

  1. Step 1: Write the proportion equation
    98.90 : 136.56 = 72.81 : x
  2. Step 2: Convert to fraction form
    98.90/136.56 = 72.81/x
  3. Step 3: Cross multiply
    98.90x = 136.56 × 72.81
  4. Step 4: Simplify right side
    98.90x = 9,942.93
  5. Step 5: Solve for x
    x = 9,942.93/98.90
  6. Step 6: Final answer
    x = 100.54

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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.