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Finding the Fourth Proportional to 258.97, 388.45 and 66.60

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Solution

The fourth proportional to 258.97, 388.45 and 66.60 is: 99.89

Step by Step Solution

  1. Step 1: Write the proportion equation
    258.97 : 388.45 = 66.60 : x
  2. Step 2: Convert to fraction form
    258.97/388.45 = 66.60/x
  3. Step 3: Cross multiply
    258.97x = 388.45 × 66.60
  4. Step 4: Simplify right side
    258.97x = 25,868.99
  5. Step 5: Solve for x
    x = 25,868.99/258.97
  6. Step 6: Final answer
    x = 99.89

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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.