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Finding the Fourth Proportional to 391.30, 540.20 and 258.66

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Solution

The fourth proportional to 391.30, 540.20 and 258.66 is: 357.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    391.30 : 540.20 = 258.66 : x
  2. Step 2: Convert to fraction form
    391.30/540.20 = 258.66/x
  3. Step 3: Cross multiply
    391.30x = 540.20 × 258.66
  4. Step 4: Simplify right side
    391.30x = 139,728.78
  5. Step 5: Solve for x
    x = 139,728.78/391.30
  6. Step 6: Final answer
    x = 357.09

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.