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Finding the Fourth Proportional to 642.54, 886.44 and 393.78

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Solution

The fourth proportional to 642.54, 886.44 and 393.78 is: 543.25

Step by Step Solution

  1. Step 1: Write the proportion equation
    642.54 : 886.44 = 393.78 : x
  2. Step 2: Convert to fraction form
    642.54/886.44 = 393.78/x
  3. Step 3: Cross multiply
    642.54x = 886.44 × 393.78
  4. Step 4: Simplify right side
    642.54x = 349,062.34
  5. Step 5: Solve for x
    x = 349,062.34/642.54
  6. Step 6: Final answer
    x = 543.25

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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.