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Finding the Fourth Proportional to 258.18, 387.19 and 121.15

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Solution

The fourth proportional to 258.18, 387.19 and 121.15 is: 181.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    258.18 : 387.19 = 121.15 : x
  2. Step 2: Convert to fraction form
    258.18/387.19 = 121.15/x
  3. Step 3: Cross multiply
    258.18x = 387.19 × 121.15
  4. Step 4: Simplify right side
    258.18x = 46,908.07
  5. Step 5: Solve for x
    x = 46,908.07/258.18
  6. Step 6: Final answer
    x = 181.69

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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.