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Finding the Fourth Proportional to 86.21, 129.31 and 47.93

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Solution

The fourth proportional to 86.21, 129.31 and 47.93 is: 71.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    86.21 : 129.31 = 47.93 : x
  2. Step 2: Convert to fraction form
    86.21/129.31 = 47.93/x
  3. Step 3: Cross multiply
    86.21x = 129.31 × 47.93
  4. Step 4: Simplify right side
    86.21x = 6,197.71
  5. Step 5: Solve for x
    x = 6,197.71/86.21
  6. Step 6: Final answer
    x = 71.90

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.