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Finding the Fourth Proportional to 81.53, 122.80 and 75.90

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Solution

The fourth proportional to 81.53, 122.80 and 75.90 is: 114.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    81.53 : 122.80 = 75.90 : x
  2. Step 2: Convert to fraction form
    81.53/122.80 = 75.90/x
  3. Step 3: Cross multiply
    81.53x = 122.80 × 75.90
  4. Step 4: Simplify right side
    81.53x = 9,320.19
  5. Step 5: Solve for x
    x = 9,320.19/81.53
  6. Step 6: Final answer
    x = 114.32

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.