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Finding the Fourth Proportional to 98.88, 136.32 and 79.68

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Solution

The fourth proportional to 98.88, 136.32 and 79.68 is: 109.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    98.88 : 136.32 = 79.68 : x
  2. Step 2: Convert to fraction form
    98.88/136.32 = 79.68/x
  3. Step 3: Cross multiply
    98.88x = 136.32 × 79.68
  4. Step 4: Simplify right side
    98.88x = 10,861.98
  5. Step 5: Solve for x
    x = 10,861.98/98.88
  6. Step 6: Final answer
    x = 109.85

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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.