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Finding the Fourth Proportional to 76.98, 115.47 and 31.38

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Solution

The fourth proportional to 76.98, 115.47 and 31.38 is: 47.07

Step by Step Solution

  1. Step 1: Write the proportion equation
    76.98 : 115.47 = 31.38 : x
  2. Step 2: Convert to fraction form
    76.98/115.47 = 31.38/x
  3. Step 3: Cross multiply
    76.98x = 115.47 × 31.38
  4. Step 4: Simplify right side
    76.98x = 3,623.45
  5. Step 5: Solve for x
    x = 3,623.45/76.98
  6. Step 6: Final answer
    x = 47.07

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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.