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Finding the Fourth Proportional to 391.62, 539.17 and 312.65

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Solution

The fourth proportional to 391.62, 539.17 and 312.65 is: 430.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    391.62 : 539.17 = 312.65 : x
  2. Step 2: Convert to fraction form
    391.62/539.17 = 312.65/x
  3. Step 3: Cross multiply
    391.62x = 539.17 × 312.65
  4. Step 4: Simplify right side
    391.62x = 168,571.50
  5. Step 5: Solve for x
    x = 168,571.50/391.62
  6. Step 6: Final answer
    x = 430.45

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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.