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Finding the Fourth Proportional to 97.80, 146.40 and 80.64

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Solution

The fourth proportional to 97.80, 146.40 and 80.64 is: 120.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    97.80 : 146.40 = 80.64 : x
  2. Step 2: Convert to fraction form
    97.80/146.40 = 80.64/x
  3. Step 3: Cross multiply
    97.80x = 146.40 × 80.64
  4. Step 4: Simplify right side
    97.80x = 11,805.70
  5. Step 5: Solve for x
    x = 11,805.70/97.80
  6. Step 6: Final answer
    x = 120.71

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.