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Finding the Fourth Proportional to 149.78, 206.64 and 87.62

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Solution

The fourth proportional to 149.78, 206.64 and 87.62 is: 120.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    149.78 : 206.64 = 87.62 : x
  2. Step 2: Convert to fraction form
    149.78/206.64 = 87.62/x
  3. Step 3: Cross multiply
    149.78x = 206.64 × 87.62
  4. Step 4: Simplify right side
    149.78x = 18,105.80
  5. Step 5: Solve for x
    x = 18,105.80/149.78
  6. Step 6: Final answer
    x = 120.88

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.