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Finding the Fourth Proportional to 408.28, 612.45 and 115.78

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Solution

The fourth proportional to 408.28, 612.45 and 115.78 is: 173.67

Step by Step Solution

  1. Step 1: Write the proportion equation
    408.28 : 612.45 = 115.78 : x
  2. Step 2: Convert to fraction form
    408.28/612.45 = 115.78/x
  3. Step 3: Cross multiply
    408.28x = 612.45 × 115.78
  4. Step 4: Simplify right side
    408.28x = 70,905.82
  5. Step 5: Solve for x
    x = 70,905.82/408.28
  6. Step 6: Final answer
    x = 173.67

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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.