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Finding the Fourth Proportional to 391.11, 538.80 and 317.91

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Solution

The fourth proportional to 391.11, 538.80 and 317.91 is: 437.96

Step by Step Solution

  1. Step 1: Write the proportion equation
    391.11 : 538.80 = 317.91 : x
  2. Step 2: Convert to fraction form
    391.11/538.80 = 317.91/x
  3. Step 3: Cross multiply
    391.11x = 538.80 × 317.91
  4. Step 4: Simplify right side
    391.11x = 171,289.91
  5. Step 5: Solve for x
    x = 171,289.91/391.11
  6. Step 6: Final answer
    x = 437.96

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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.