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Finding the Fourth Proportional to 378.20, 521.56 and 289.64

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Solution

The fourth proportional to 378.20, 521.56 and 289.64 is: 399.43

Step by Step Solution

  1. Step 1: Write the proportion equation
    378.20 : 521.56 = 289.64 : x
  2. Step 2: Convert to fraction form
    378.20/521.56 = 289.64/x
  3. Step 3: Cross multiply
    378.20x = 521.56 × 289.64
  4. Step 4: Simplify right side
    378.20x = 151,064.64
  5. Step 5: Solve for x
    x = 151,064.64/378.20
  6. Step 6: Final answer
    x = 399.43

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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.