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Finding the Fourth Proportional to 99.20, 136.80 and 93.12

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Solution

The fourth proportional to 99.20, 136.80 and 93.12 is: 128.42

Step by Step Solution

  1. Step 1: Write the proportion equation
    99.20 : 136.80 = 93.12 : x
  2. Step 2: Convert to fraction form
    99.20/136.80 = 93.12/x
  3. Step 3: Cross multiply
    99.20x = 136.80 × 93.12
  4. Step 4: Simplify right side
    99.20x = 12,738.82
  5. Step 5: Solve for x
    x = 12,738.82/99.20
  6. Step 6: Final answer
    x = 128.42

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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.