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Finding the Fourth Proportional to 76.98, 115.25 and 66.70

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Solution

The fourth proportional to 76.98, 115.25 and 66.70 is: 99.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    76.98 : 115.25 = 66.70 : x
  2. Step 2: Convert to fraction form
    76.98/115.25 = 66.70/x
  3. Step 3: Cross multiply
    76.98x = 115.25 × 66.70
  4. Step 4: Simplify right side
    76.98x = 7,686.99
  5. Step 5: Solve for x
    x = 7,686.99/76.98
  6. Step 6: Final answer
    x = 99.85

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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.