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Finding the Fourth Proportional to 82.39, 123.09 and 61.45

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Solution

The fourth proportional to 82.39, 123.09 and 61.45 is: 91.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    82.39 : 123.09 = 61.45 : x
  2. Step 2: Convert to fraction form
    82.39/123.09 = 61.45/x
  3. Step 3: Cross multiply
    82.39x = 123.09 × 61.45
  4. Step 4: Simplify right side
    82.39x = 7,563.57
  5. Step 5: Solve for x
    x = 7,563.57/82.39
  6. Step 6: Final answer
    x = 91.80

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.