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Finding the Fourth Proportional to 391.46, 540.21 and 216.81

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Solution

The fourth proportional to 391.46, 540.21 and 216.81 is: 299.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    391.46 : 540.21 = 216.81 : x
  2. Step 2: Convert to fraction form
    391.46/540.21 = 216.81/x
  3. Step 3: Cross multiply
    391.46x = 540.21 × 216.81
  4. Step 4: Simplify right side
    391.46x = 117,122.93
  5. Step 5: Solve for x
    x = 117,122.93/391.46
  6. Step 6: Final answer
    x = 299.20

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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.