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Finding the Fourth Proportional to 99.09, 136.47 and 87.42

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Solution

The fourth proportional to 99.09, 136.47 and 87.42 is: 120.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    99.09 : 136.47 = 87.42 : x
  2. Step 2: Convert to fraction form
    99.09/136.47 = 87.42/x
  3. Step 3: Cross multiply
    99.09x = 136.47 × 87.42
  4. Step 4: Simplify right side
    99.09x = 11,930.21
  5. Step 5: Solve for x
    x = 11,930.21/99.09
  6. Step 6: Final answer
    x = 120.40

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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.