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Finding the Fourth Proportional to 70.56, 105.20 and 66.72

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Solution

The fourth proportional to 70.56, 105.20 and 66.72 is: 99.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    70.56 : 105.20 = 66.72 : x
  2. Step 2: Convert to fraction form
    70.56/105.20 = 66.72/x
  3. Step 3: Cross multiply
    70.56x = 105.20 × 66.72
  4. Step 4: Simplify right side
    70.56x = 7,018.94
  5. Step 5: Solve for x
    x = 7,018.94/70.56
  6. Step 6: Final answer
    x = 99.47

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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.