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Finding the Fourth Proportional to 98.90, 136.05 and 81.62

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Solution

The fourth proportional to 98.90, 136.05 and 81.62 is: 112.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    98.90 : 136.05 = 81.62 : x
  2. Step 2: Convert to fraction form
    98.90/136.05 = 81.62/x
  3. Step 3: Cross multiply
    98.90x = 136.05 × 81.62
  4. Step 4: Simplify right side
    98.90x = 11,104.40
  5. Step 5: Solve for x
    x = 11,104.40/98.90
  6. Step 6: Final answer
    x = 112.28

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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.