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Finding the Fourth Proportional to 149.86, 206.79 and 87.70

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Solution

The fourth proportional to 149.86, 206.79 and 87.70 is: 121.02

Step by Step Solution

  1. Step 1: Write the proportion equation
    149.86 : 206.79 = 87.70 : x
  2. Step 2: Convert to fraction form
    149.86/206.79 = 87.70/x
  3. Step 3: Cross multiply
    149.86x = 206.79 × 87.70
  4. Step 4: Simplify right side
    149.86x = 18,135.48
  5. Step 5: Solve for x
    x = 18,135.48/149.86
  6. Step 6: Final answer
    x = 121.02

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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.