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Finding the Fourth Proportional to 76.81, 115.14 and 49.31

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Solution

The fourth proportional to 76.81, 115.14 and 49.31 is: 73.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    76.81 : 115.14 = 49.31 : x
  2. Step 2: Convert to fraction form
    76.81/115.14 = 49.31/x
  3. Step 3: Cross multiply
    76.81x = 115.14 × 49.31
  4. Step 4: Simplify right side
    76.81x = 5,677.08
  5. Step 5: Solve for x
    x = 5,677.08/76.81
  6. Step 6: Final answer
    x = 73.91

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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.