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Finding the Fourth Proportional to 86.79, 130.17 and 31.94

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Solution

The fourth proportional to 86.79, 130.17 and 31.94 is: 47.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    86.79 : 130.17 = 31.94 : x
  2. Step 2: Convert to fraction form
    86.79/130.17 = 31.94/x
  3. Step 3: Cross multiply
    86.79x = 130.17 × 31.94
  4. Step 4: Simplify right side
    86.79x = 4,157.59
  5. Step 5: Solve for x
    x = 4,157.59/86.79
  6. Step 6: Final answer
    x = 47.90

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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.