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Finding the Fourth Proportional to 391.50, 539.78 and 313.08

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Solution

The fourth proportional to 391.50, 539.78 and 313.08 is: 431.65

Step by Step Solution

  1. Step 1: Write the proportion equation
    391.50 : 539.78 = 313.08 : x
  2. Step 2: Convert to fraction form
    391.50/539.78 = 313.08/x
  3. Step 3: Cross multiply
    391.50x = 539.78 × 313.08
  4. Step 4: Simplify right side
    391.50x = 168,992.76
  5. Step 5: Solve for x
    x = 168,992.76/391.50
  6. Step 6: Final answer
    x = 431.65

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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.