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Finding the Fourth Proportional to 390.85, 538.14 and 331.71

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Solution

The fourth proportional to 390.85, 538.14 and 331.71 is: 456.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.85 : 538.14 = 331.71 : x
  2. Step 2: Convert to fraction form
    390.85/538.14 = 331.71/x
  3. Step 3: Cross multiply
    390.85x = 538.14 × 331.71
  4. Step 4: Simplify right side
    390.85x = 178,506.42
  5. Step 5: Solve for x
    x = 178,506.42/390.85
  6. Step 6: Final answer
    x = 456.71

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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.