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Finding the Fourth Proportional to 86.71, 130.06 and 31.87

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Solution

The fourth proportional to 86.71, 130.06 and 31.87 is: 47.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    86.71 : 130.06 = 31.87 : x
  2. Step 2: Convert to fraction form
    86.71/130.06 = 31.87/x
  3. Step 3: Cross multiply
    86.71x = 130.06 × 31.87
  4. Step 4: Simplify right side
    86.71x = 4,144.73
  5. Step 5: Solve for x
    x = 4,144.73/86.71
  6. Step 6: Final answer
    x = 47.80

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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.