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Finding the Fourth Proportional to 378.20, 521.34 and 261.56

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Solution

The fourth proportional to 378.20, 521.34 and 261.56 is: 360.55

Step by Step Solution

  1. Step 1: Write the proportion equation
    378.20 : 521.34 = 261.56 : x
  2. Step 2: Convert to fraction form
    378.20/521.34 = 261.56/x
  3. Step 3: Cross multiply
    378.20x = 521.34 × 261.56
  4. Step 4: Simplify right side
    378.20x = 136,361.69
  5. Step 5: Solve for x
    x = 136,361.69/378.20
  6. Step 6: Final answer
    x = 360.55

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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.