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Finding the Fourth Proportional to 642.54, 886.63 and 393.92

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Solution

The fourth proportional to 642.54, 886.63 and 393.92 is: 543.56

Step by Step Solution

  1. Step 1: Write the proportion equation
    642.54 : 886.63 = 393.92 : x
  2. Step 2: Convert to fraction form
    642.54/886.63 = 393.92/x
  3. Step 3: Cross multiply
    642.54x = 886.63 × 393.92
  4. Step 4: Simplify right side
    642.54x = 349,261.29
  5. Step 5: Solve for x
    x = 349,261.29/642.54
  6. Step 6: Final answer
    x = 543.56

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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.