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Finding the Fourth Proportional to 70.87, 106.31 and 66.91

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Solution

The fourth proportional to 70.87, 106.31 and 66.91 is: 100.37

Step by Step Solution

  1. Step 1: Write the proportion equation
    70.87 : 106.31 = 66.91 : x
  2. Step 2: Convert to fraction form
    70.87/106.31 = 66.91/x
  3. Step 3: Cross multiply
    70.87x = 106.31 × 66.91
  4. Step 4: Simplify right side
    70.87x = 7,113.20
  5. Step 5: Solve for x
    x = 7,113.20/70.87
  6. Step 6: Final answer
    x = 100.37

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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.