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Finding the Fourth Proportional to 72.12, 99.42 and 69.39

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Solution

The fourth proportional to 72.12, 99.42 and 69.39 is: 95.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    72.12 : 99.42 = 69.39 : x
  2. Step 2: Convert to fraction form
    72.12/99.42 = 69.39/x
  3. Step 3: Cross multiply
    72.12x = 99.42 × 69.39
  4. Step 4: Simplify right side
    72.12x = 6,898.75
  5. Step 5: Solve for x
    x = 6,898.75/72.12
  6. Step 6: Final answer
    x = 95.66

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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.