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Finding the Fourth Proportional to 393.78, 591.48 and 387.30

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Solution

The fourth proportional to 393.78, 591.48 and 387.30 is: 581.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    393.78 : 591.48 = 387.30 : x
  2. Step 2: Convert to fraction form
    393.78/591.48 = 387.30/x
  3. Step 3: Cross multiply
    393.78x = 591.48 × 387.30
  4. Step 4: Simplify right side
    393.78x = 229,080.20
  5. Step 5: Solve for x
    x = 229,080.20/393.78
  6. Step 6: Final answer
    x = 581.75

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.