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Finding the Fourth Proportional to 258.09, 387.21 and 113.91

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Solution

The fourth proportional to 258.09, 387.21 and 113.91 is: 170.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    258.09 : 387.21 = 113.91 : x
  2. Step 2: Convert to fraction form
    258.09/387.21 = 113.91/x
  3. Step 3: Cross multiply
    258.09x = 387.21 × 113.91
  4. Step 4: Simplify right side
    258.09x = 44,106.52
  5. Step 5: Solve for x
    x = 44,106.52/258.09
  6. Step 6: Final answer
    x = 170.90

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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.