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Finding the Fourth Proportional to 82.60, 123.80 and 61.20

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Solution

The fourth proportional to 82.60, 123.80 and 61.20 is: 91.73

Step by Step Solution

  1. Step 1: Write the proportion equation
    82.60 : 123.80 = 61.20 : x
  2. Step 2: Convert to fraction form
    82.60/123.80 = 61.20/x
  3. Step 3: Cross multiply
    82.60x = 123.80 × 61.20
  4. Step 4: Simplify right side
    82.60x = 7,576.56
  5. Step 5: Solve for x
    x = 7,576.56/82.60
  6. Step 6: Final answer
    x = 91.73

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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.