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Finding the Fourth Proportional to 122.56, 183.70 and 76.80

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Solution

The fourth proportional to 122.56, 183.70 and 76.80 is: 115.11

Step by Step Solution

  1. Step 1: Write the proportion equation
    122.56 : 183.70 = 76.80 : x
  2. Step 2: Convert to fraction form
    122.56/183.70 = 76.80/x
  3. Step 3: Cross multiply
    122.56x = 183.70 × 76.80
  4. Step 4: Simplify right side
    122.56x = 14,108.16
  5. Step 5: Solve for x
    x = 14,108.16/122.56
  6. Step 6: Final answer
    x = 115.11

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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.