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Finding the Fourth Proportional to 258.36, 387.55 and 85.04

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Solution

The fourth proportional to 258.36, 387.55 and 85.04 is: 127.55

Step by Step Solution

  1. Step 1: Write the proportion equation
    258.36 : 387.55 = 85.04 : x
  2. Step 2: Convert to fraction form
    258.36/387.55 = 85.04/x
  3. Step 3: Cross multiply
    258.36x = 387.55 × 85.04
  4. Step 4: Simplify right side
    258.36x = 32,954.89
  5. Step 5: Solve for x
    x = 32,954.89/258.36
  6. Step 6: Final answer
    x = 127.55

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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.