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Finding the Fourth Proportional to 82.87, 123.70 and 76.85

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Solution

The fourth proportional to 82.87, 123.70 and 76.85 is: 114.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    82.87 : 123.70 = 76.85 : x
  2. Step 2: Convert to fraction form
    82.87/123.70 = 76.85/x
  3. Step 3: Cross multiply
    82.87x = 123.70 × 76.85
  4. Step 4: Simplify right side
    82.87x = 9,506.07
  5. Step 5: Solve for x
    x = 9,506.07/82.87
  6. Step 6: Final answer
    x = 114.71

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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.