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Finding the Fourth Proportional to 149.40, 206.15 and 83.91

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Solution

The fourth proportional to 149.40, 206.15 and 83.91 is: 115.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    149.40 : 206.15 = 83.91 : x
  2. Step 2: Convert to fraction form
    149.40/206.15 = 83.91/x
  3. Step 3: Cross multiply
    149.40x = 206.15 × 83.91
  4. Step 4: Simplify right side
    149.40x = 17,297.02
  5. Step 5: Solve for x
    x = 17,297.02/149.40
  6. Step 6: Final answer
    x = 115.78

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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.