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Finding the Fourth Proportional to 258.16, 387.31 and 121.28

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Solution

The fourth proportional to 258.16, 387.31 and 121.28 is: 181.96

Step by Step Solution

  1. Step 1: Write the proportion equation
    258.16 : 387.31 = 121.28 : x
  2. Step 2: Convert to fraction form
    258.16/387.31 = 121.28/x
  3. Step 3: Cross multiply
    258.16x = 387.31 × 121.28
  4. Step 4: Simplify right side
    258.16x = 46,972.96
  5. Step 5: Solve for x
    x = 46,972.96/258.16
  6. Step 6: Final answer
    x = 181.96

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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.