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Finding the Fourth Proportional to 70.72, 105.36 and 66.30

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Solution

The fourth proportional to 70.72, 105.36 and 66.30 is: 98.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    70.72 : 105.36 = 66.30 : x
  2. Step 2: Convert to fraction form
    70.72/105.36 = 66.30/x
  3. Step 3: Cross multiply
    70.72x = 105.36 × 66.30
  4. Step 4: Simplify right side
    70.72x = 6,985.37
  5. Step 5: Solve for x
    x = 6,985.37/70.72
  6. Step 6: Final answer
    x = 98.78

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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.