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Finding the Fourth Proportional to 391.15, 539.80 and 216.49

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Solution

The fourth proportional to 391.15, 539.80 and 216.49 is: 298.77

Step by Step Solution

  1. Step 1: Write the proportion equation
    391.15 : 539.80 = 216.49 : x
  2. Step 2: Convert to fraction form
    391.15/539.80 = 216.49/x
  3. Step 3: Cross multiply
    391.15x = 539.80 × 216.49
  4. Step 4: Simplify right side
    391.15x = 116,863.16
  5. Step 5: Solve for x
    x = 116,863.16/391.15
  6. Step 6: Final answer
    x = 298.77

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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.