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Finding the Fourth Proportional to 258.62, 390.26 and 256.59

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Solution

The fourth proportional to 258.62, 390.26 and 256.59 is: 387.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    258.62 : 390.26 = 256.59 : x
  2. Step 2: Convert to fraction form
    258.62/390.26 = 256.59/x
  3. Step 3: Cross multiply
    258.62x = 390.26 × 256.59
  4. Step 4: Simplify right side
    258.62x = 100,137.45
  5. Step 5: Solve for x
    x = 100,137.45/258.62
  6. Step 6: Final answer
    x = 387.21

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.