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Finding the Fourth Proportional to 72.38, 99.91 and 47.81

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Solution

The fourth proportional to 72.38, 99.91 and 47.81 is: 65.99

Step by Step Solution

  1. Step 1: Write the proportion equation
    72.38 : 99.91 = 47.81 : x
  2. Step 2: Convert to fraction form
    72.38/99.91 = 47.81/x
  3. Step 3: Cross multiply
    72.38x = 99.91 × 47.81
  4. Step 4: Simplify right side
    72.38x = 4,776.31
  5. Step 5: Solve for x
    x = 4,776.31/72.38
  6. Step 6: Final answer
    x = 65.99

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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.