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Finding the Fourth Proportional to 642.44, 886.65 and 393.79

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Solution

The fourth proportional to 642.44, 886.65 and 393.79 is: 543.48

Step by Step Solution

  1. Step 1: Write the proportion equation
    642.44 : 886.65 = 393.79 : x
  2. Step 2: Convert to fraction form
    642.44/886.65 = 393.79/x
  3. Step 3: Cross multiply
    642.44x = 886.65 × 393.79
  4. Step 4: Simplify right side
    642.44x = 349,153.90
  5. Step 5: Solve for x
    x = 349,153.90/642.44
  6. Step 6: Final answer
    x = 543.48

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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.