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Finding the Fourth Proportional to 76.76, 115.20 and 42.08

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Solution

The fourth proportional to 76.76, 115.20 and 42.08 is: 63.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    76.76 : 115.20 = 42.08 : x
  2. Step 2: Convert to fraction form
    76.76/115.20 = 42.08/x
  3. Step 3: Cross multiply
    76.76x = 115.20 × 42.08
  4. Step 4: Simplify right side
    76.76x = 4,847.62
  5. Step 5: Solve for x
    x = 4,847.62/76.76
  6. Step 6: Final answer
    x = 63.15

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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.