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Finding the Fourth Proportional to 66.15, 91.31 and 47.79

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Solution

The fourth proportional to 66.15, 91.31 and 47.79 is: 65.96

Step by Step Solution

  1. Step 1: Write the proportion equation
    66.15 : 91.31 = 47.79 : x
  2. Step 2: Convert to fraction form
    66.15/91.31 = 47.79/x
  3. Step 3: Cross multiply
    66.15x = 91.31 × 47.79
  4. Step 4: Simplify right side
    66.15x = 4,363.47
  5. Step 5: Solve for x
    x = 4,363.47/66.15
  6. Step 6: Final answer
    x = 65.96

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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.