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Finding the Fourth Proportional to 82.90, 123.81 and 69.39

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Solution

The fourth proportional to 82.90, 123.81 and 69.39 is: 103.62

Step by Step Solution

  1. Step 1: Write the proportion equation
    82.90 : 123.81 = 69.39 : x
  2. Step 2: Convert to fraction form
    82.90/123.81 = 69.39/x
  3. Step 3: Cross multiply
    82.90x = 123.81 × 69.39
  4. Step 4: Simplify right side
    82.90x = 8,590.38
  5. Step 5: Solve for x
    x = 8,590.38/82.90
  6. Step 6: Final answer
    x = 103.62

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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.