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Finding the Fourth Proportional to 120.78, 181.62 and 80.28

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Solution

The fourth proportional to 120.78, 181.62 and 80.28 is: 120.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    120.78 : 181.62 = 80.28 : x
  2. Step 2: Convert to fraction form
    120.78/181.62 = 80.28/x
  3. Step 3: Cross multiply
    120.78x = 181.62 × 80.28
  4. Step 4: Simplify right side
    120.78x = 14,580.45
  5. Step 5: Solve for x
    x = 14,580.45/120.78
  6. Step 6: Final answer
    x = 120.72

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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.