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Finding the Fourth Proportional to 393.43, 542.95 and 218.78

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Solution

The fourth proportional to 393.43, 542.95 and 218.78 is: 301.92

Step by Step Solution

  1. Step 1: Write the proportion equation
    393.43 : 542.95 = 218.78 : x
  2. Step 2: Convert to fraction form
    393.43/542.95 = 218.78/x
  3. Step 3: Cross multiply
    393.43x = 542.95 × 218.78
  4. Step 4: Simplify right side
    393.43x = 118,783.34
  5. Step 5: Solve for x
    x = 118,783.34/393.43
  6. Step 6: Final answer
    x = 301.92

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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.