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Finding the Fourth Proportional to 391.64, 540 and 321.48

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Solution

The fourth proportional to 391.64, 540 and 321.48 is: 443.26

Step by Step Solution

  1. Step 1: Write the proportion equation
    391.64 : 540 = 321.48 : x
  2. Step 2: Convert to fraction form
    391.64/540 = 321.48/x
  3. Step 3: Cross multiply
    391.64x = 540 × 321.48
  4. Step 4: Simplify right side
    391.64x = 173,599.20
  5. Step 5: Solve for x
    x = 173,599.20/391.64
  6. Step 6: Final answer
    x = 443.26

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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.