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Finding the Fourth Proportional to 76.31, 105.32 and 47.21

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Solution

The fourth proportional to 76.31, 105.32 and 47.21 is: 65.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    76.31 : 105.32 = 47.21 : x
  2. Step 2: Convert to fraction form
    76.31/105.32 = 47.21/x
  3. Step 3: Cross multiply
    76.31x = 105.32 × 47.21
  4. Step 4: Simplify right side
    76.31x = 4,971.97
  5. Step 5: Solve for x
    x = 4,971.97/76.31
  6. Step 6: Final answer
    x = 65.15

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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.