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Finding the Fourth Proportional to 97.80, 145.99 and 81.56

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Solution

The fourth proportional to 97.80, 145.99 and 81.56 is: 121.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    97.80 : 145.99 = 81.56 : x
  2. Step 2: Convert to fraction form
    97.80/145.99 = 81.56/x
  3. Step 3: Cross multiply
    97.80x = 145.99 × 81.56
  4. Step 4: Simplify right side
    97.80x = 11,906.94
  5. Step 5: Solve for x
    x = 11,906.94/97.80
  6. Step 6: Final answer
    x = 121.75

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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.