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Finding the Fourth Proportional to 120.78, 181.26 and 90.54

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Solution

The fourth proportional to 120.78, 181.26 and 90.54 is: 135.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    120.78 : 181.26 = 90.54 : x
  2. Step 2: Convert to fraction form
    120.78/181.26 = 90.54/x
  3. Step 3: Cross multiply
    120.78x = 181.26 × 90.54
  4. Step 4: Simplify right side
    120.78x = 16,411.28
  5. Step 5: Solve for x
    x = 16,411.28/120.78
  6. Step 6: Final answer
    x = 135.88

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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.