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Finding the Fourth Proportional to 320.78, 481.20 and 115.40

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Solution

The fourth proportional to 320.78, 481.20 and 115.40 is: 173.11

Step by Step Solution

  1. Step 1: Write the proportion equation
    320.78 : 481.20 = 115.40 : x
  2. Step 2: Convert to fraction form
    320.78/481.20 = 115.40/x
  3. Step 3: Cross multiply
    320.78x = 481.20 × 115.40
  4. Step 4: Simplify right side
    320.78x = 55,528.07
  5. Step 5: Solve for x
    x = 55,528.07/320.78
  6. Step 6: Final answer
    x = 173.11

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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.