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Finding the Fourth Proportional to 70.61, 105.79 and 39.72

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Solution

The fourth proportional to 70.61, 105.79 and 39.72 is: 59.51

Step by Step Solution

  1. Step 1: Write the proportion equation
    70.61 : 105.79 = 39.72 : x
  2. Step 2: Convert to fraction form
    70.61/105.79 = 39.72/x
  3. Step 3: Cross multiply
    70.61x = 105.79 × 39.72
  4. Step 4: Simplify right side
    70.61x = 4,201.98
  5. Step 5: Solve for x
    x = 4,201.98/70.61
  6. Step 6: Final answer
    x = 59.51

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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.