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Finding the Fourth Proportional to 642.89, 886.75 and 393.89

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Solution

The fourth proportional to 642.89, 886.75 and 393.89 is: 543.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    642.89 : 886.75 = 393.89 : x
  2. Step 2: Convert to fraction form
    642.89/886.75 = 393.89/x
  3. Step 3: Cross multiply
    642.89x = 886.75 × 393.89
  4. Step 4: Simplify right side
    642.89x = 349,281.96
  5. Step 5: Solve for x
    x = 349,281.96/642.89
  6. Step 6: Final answer
    x = 543.30

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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.