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Finding the Fourth Proportional to 76.83, 115.86 and 71.78

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Solution

The fourth proportional to 76.83, 115.86 and 71.78 is: 108.24

Step by Step Solution

  1. Step 1: Write the proportion equation
    76.83 : 115.86 = 71.78 : x
  2. Step 2: Convert to fraction form
    76.83/115.86 = 71.78/x
  3. Step 3: Cross multiply
    76.83x = 115.86 × 71.78
  4. Step 4: Simplify right side
    76.83x = 8,315.85
  5. Step 5: Solve for x
    x = 8,315.85/76.83
  6. Step 6: Final answer
    x = 108.24

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.