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Finding the Fourth Proportional to 76.72, 115 and 38.20

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Solution

The fourth proportional to 76.72, 115 and 38.20 is: 57.26

Step by Step Solution

  1. Step 1: Write the proportion equation
    76.72 : 115 = 38.20 : x
  2. Step 2: Convert to fraction form
    76.72/115 = 38.20/x
  3. Step 3: Cross multiply
    76.72x = 115 × 38.20
  4. Step 4: Simplify right side
    76.72x = 4,393
  5. Step 5: Solve for x
    x = 4,393/76.72
  6. Step 6: Final answer
    x = 57.26

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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.