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Finding the Fourth Proportional to 390.42, 538.73 and 331.64

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Solution

The fourth proportional to 390.42, 538.73 and 331.64 is: 457.62

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.42 : 538.73 = 331.64 : x
  2. Step 2: Convert to fraction form
    390.42/538.73 = 331.64/x
  3. Step 3: Cross multiply
    390.42x = 538.73 × 331.64
  4. Step 4: Simplify right side
    390.42x = 178,665.43
  5. Step 5: Solve for x
    x = 178,665.43/390.42
  6. Step 6: Final answer
    x = 457.62

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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.