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Finding the Fourth Proportional to 70.58, 105.12 and 69.78

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Solution

The fourth proportional to 70.58, 105.12 and 69.78 is: 103.93

Step by Step Solution

  1. Step 1: Write the proportion equation
    70.58 : 105.12 = 69.78 : x
  2. Step 2: Convert to fraction form
    70.58/105.12 = 69.78/x
  3. Step 3: Cross multiply
    70.58x = 105.12 × 69.78
  4. Step 4: Simplify right side
    70.58x = 7,335.71
  5. Step 5: Solve for x
    x = 7,335.71/70.58
  6. Step 6: Final answer
    x = 103.93

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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.