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Finding the Fourth Proportional to 455.49, 628.49 and 393.80

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Solution

The fourth proportional to 455.49, 628.49 and 393.80 is: 543.36

Step by Step Solution

  1. Step 1: Write the proportion equation
    455.49 : 628.49 = 393.80 : x
  2. Step 2: Convert to fraction form
    455.49/628.49 = 393.80/x
  3. Step 3: Cross multiply
    455.49x = 628.49 × 393.80
  4. Step 4: Simplify right side
    455.49x = 247,497.20
  5. Step 5: Solve for x
    x = 247,497.20/455.49
  6. Step 6: Final answer
    x = 543.36

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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.