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Finding the Fourth Proportional to 378.54, 521.76 and 311.88

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Solution

The fourth proportional to 378.54, 521.76 and 311.88 is: 429.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    378.54 : 521.76 = 311.88 : x
  2. Step 2: Convert to fraction form
    378.54/521.76 = 311.88/x
  3. Step 3: Cross multiply
    378.54x = 521.76 × 311.88
  4. Step 4: Simplify right side
    378.54x = 162,726.51
  5. Step 5: Solve for x
    x = 162,726.51/378.54
  6. Step 6: Final answer
    x = 429.88

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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.