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Finding the Fourth Proportional to 391.17, 539.78 and 216.51

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Solution

The fourth proportional to 391.17, 539.78 and 216.51 is: 298.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    391.17 : 539.78 = 216.51 : x
  2. Step 2: Convert to fraction form
    391.17/539.78 = 216.51/x
  3. Step 3: Cross multiply
    391.17x = 539.78 × 216.51
  4. Step 4: Simplify right side
    391.17x = 116,867.77
  5. Step 5: Solve for x
    x = 116,867.77/391.17
  6. Step 6: Final answer
    x = 298.76

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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.