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Finding the Fourth Proportional to 72.25, 99.81 and 66.39

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Solution

The fourth proportional to 72.25, 99.81 and 66.39 is: 91.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    72.25 : 99.81 = 66.39 : x
  2. Step 2: Convert to fraction form
    72.25/99.81 = 66.39/x
  3. Step 3: Cross multiply
    72.25x = 99.81 × 66.39
  4. Step 4: Simplify right side
    72.25x = 6,626.39
  5. Step 5: Solve for x
    x = 6,626.39/72.25
  6. Step 6: Final answer
    x = 91.71

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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.