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Finding the Fourth Proportional to 83.68, 115.45 and 61.81

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Solution

The fourth proportional to 83.68, 115.45 and 61.81 is: 85.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    83.68 : 115.45 = 61.81 : x
  2. Step 2: Convert to fraction form
    83.68/115.45 = 61.81/x
  3. Step 3: Cross multiply
    83.68x = 115.45 × 61.81
  4. Step 4: Simplify right side
    83.68x = 7,135.96
  5. Step 5: Solve for x
    x = 7,135.96/83.68
  6. Step 6: Final answer
    x = 85.28

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.