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Finding the Fourth Proportional to 82.53, 113.79 and 78.21

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Solution

The fourth proportional to 82.53, 113.79 and 78.21 is: 107.83

Step by Step Solution

  1. Step 1: Write the proportion equation
    82.53 : 113.79 = 78.21 : x
  2. Step 2: Convert to fraction form
    82.53/113.79 = 78.21/x
  3. Step 3: Cross multiply
    82.53x = 113.79 × 78.21
  4. Step 4: Simplify right side
    82.53x = 8,899.52
  5. Step 5: Solve for x
    x = 8,899.52/82.53
  6. Step 6: Final answer
    x = 107.83

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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.