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Finding the Fourth Proportional to 378.90, 523.13 and 305.55

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Solution

The fourth proportional to 378.90, 523.13 and 305.55 is: 421.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    378.90 : 523.13 = 305.55 : x
  2. Step 2: Convert to fraction form
    378.90/523.13 = 305.55/x
  3. Step 3: Cross multiply
    378.90x = 523.13 × 305.55
  4. Step 4: Simplify right side
    378.90x = 159,840.84
  5. Step 5: Solve for x
    x = 159,840.84/378.90
  6. Step 6: Final answer
    x = 421.85

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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.