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Finding the Fourth Proportional to 86.30, 129.47 and 47.76

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Solution

The fourth proportional to 86.30, 129.47 and 47.76 is: 71.65

Step by Step Solution

  1. Step 1: Write the proportion equation
    86.30 : 129.47 = 47.76 : x
  2. Step 2: Convert to fraction form
    86.30/129.47 = 47.76/x
  3. Step 3: Cross multiply
    86.30x = 129.47 × 47.76
  4. Step 4: Simplify right side
    86.30x = 6,183.81
  5. Step 5: Solve for x
    x = 6,183.81/86.30
  6. Step 6: Final answer
    x = 71.65

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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.