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Finding the Fourth Proportional to 391.12, 539.75 and 216.45

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Solution

The fourth proportional to 391.12, 539.75 and 216.45 is: 298.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    391.12 : 539.75 = 216.45 : x
  2. Step 2: Convert to fraction form
    391.12/539.75 = 216.45/x
  3. Step 3: Cross multiply
    391.12x = 539.75 × 216.45
  4. Step 4: Simplify right side
    391.12x = 116,828.89
  5. Step 5: Solve for x
    x = 116,828.89/391.12
  6. Step 6: Final answer
    x = 298.70

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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.