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Finding the Fourth Proportional to 120.78, 181.32 and 102.86

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Solution

The fourth proportional to 120.78, 181.32 and 102.86 is: 154.41

Step by Step Solution

  1. Step 1: Write the proportion equation
    120.78 : 181.32 = 102.86 : x
  2. Step 2: Convert to fraction form
    120.78/181.32 = 102.86/x
  3. Step 3: Cross multiply
    120.78x = 181.32 × 102.86
  4. Step 4: Simplify right side
    120.78x = 18,649.15
  5. Step 5: Solve for x
    x = 18,649.15/120.78
  6. Step 6: Final answer
    x = 154.41

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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.