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Finding the Fourth Proportional to 76.97, 115.34 and 42.70

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Solution

The fourth proportional to 76.97, 115.34 and 42.70 is: 63.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    76.97 : 115.34 = 42.70 : x
  2. Step 2: Convert to fraction form
    76.97/115.34 = 42.70/x
  3. Step 3: Cross multiply
    76.97x = 115.34 × 42.70
  4. Step 4: Simplify right side
    76.97x = 4,924.52
  5. Step 5: Solve for x
    x = 4,924.52/76.97
  6. Step 6: Final answer
    x = 63.98

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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.