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Finding the Fourth Proportional to 98.88, 136.08 and 76.80

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Solution

The fourth proportional to 98.88, 136.08 and 76.80 is: 105.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    98.88 : 136.08 = 76.80 : x
  2. Step 2: Convert to fraction form
    98.88/136.08 = 76.80/x
  3. Step 3: Cross multiply
    98.88x = 136.08 × 76.80
  4. Step 4: Simplify right side
    98.88x = 10,450.94
  5. Step 5: Solve for x
    x = 10,450.94/98.88
  6. Step 6: Final answer
    x = 105.69

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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.