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Finding the Fourth Proportional to 82.91, 123.45 and 77.90

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Solution

The fourth proportional to 82.91, 123.45 and 77.90 is: 115.99

Step by Step Solution

  1. Step 1: Write the proportion equation
    82.91 : 123.45 = 77.90 : x
  2. Step 2: Convert to fraction form
    82.91/123.45 = 77.90/x
  3. Step 3: Cross multiply
    82.91x = 123.45 × 77.90
  4. Step 4: Simplify right side
    82.91x = 9,617.06
  5. Step 5: Solve for x
    x = 9,617.06/82.91
  6. Step 6: Final answer
    x = 115.99

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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.