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Finding the Fourth Proportional to 393.90, 543.33 and 306.78

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Solution

The fourth proportional to 393.90, 543.33 and 306.78 is: 423.16

Step by Step Solution

  1. Step 1: Write the proportion equation
    393.90 : 543.33 = 306.78 : x
  2. Step 2: Convert to fraction form
    393.90/543.33 = 306.78/x
  3. Step 3: Cross multiply
    393.90x = 543.33 × 306.78
  4. Step 4: Simplify right side
    393.90x = 166,682.78
  5. Step 5: Solve for x
    x = 166,682.78/393.90
  6. Step 6: Final answer
    x = 423.16

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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.