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Finding the Fourth Proportional to 120.87, 181.31 and 66.87

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Solution

The fourth proportional to 120.87, 181.31 and 66.87 is: 100.31

Step by Step Solution

  1. Step 1: Write the proportion equation
    120.87 : 181.31 = 66.87 : x
  2. Step 2: Convert to fraction form
    120.87/181.31 = 66.87/x
  3. Step 3: Cross multiply
    120.87x = 181.31 × 66.87
  4. Step 4: Simplify right side
    120.87x = 12,123.87
  5. Step 5: Solve for x
    x = 12,123.87/120.87
  6. Step 6: Final answer
    x = 100.31

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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.