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Finding the Fourth Proportional to 391.99, 540.39 and 313.57

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Solution

The fourth proportional to 391.99, 540.39 and 313.57 is: 432.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    391.99 : 540.39 = 313.57 : x
  2. Step 2: Convert to fraction form
    391.99/540.39 = 313.57/x
  3. Step 3: Cross multiply
    391.99x = 540.39 × 313.57
  4. Step 4: Simplify right side
    391.99x = 169,450.09
  5. Step 5: Solve for x
    x = 169,450.09/391.99
  6. Step 6: Final answer
    x = 432.28

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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.