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Finding the Fourth Proportional to 378.45, 521.73 and 311.84

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Solution

The fourth proportional to 378.45, 521.73 and 311.84 is: 429.89

Step by Step Solution

  1. Step 1: Write the proportion equation
    378.45 : 521.73 = 311.84 : x
  2. Step 2: Convert to fraction form
    378.45/521.73 = 311.84/x
  3. Step 3: Cross multiply
    378.45x = 521.73 × 311.84
  4. Step 4: Simplify right side
    378.45x = 162,693.67
  5. Step 5: Solve for x
    x = 162,693.67/378.45
  6. Step 6: Final answer
    x = 429.89

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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.