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Finding the Fourth Proportional to 97.20, 145.62 and 66.78

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Solution

The fourth proportional to 97.20, 145.62 and 66.78 is: 100.05

Step by Step Solution

  1. Step 1: Write the proportion equation
    97.20 : 145.62 = 66.78 : x
  2. Step 2: Convert to fraction form
    97.20/145.62 = 66.78/x
  3. Step 3: Cross multiply
    97.20x = 145.62 × 66.78
  4. Step 4: Simplify right side
    97.20x = 9,724.50
  5. Step 5: Solve for x
    x = 9,724.50/97.20
  6. Step 6: Final answer
    x = 100.05

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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.