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Finding the Fourth Proportional to 642.72, 887.04 and 393.96

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Solution

The fourth proportional to 642.72, 887.04 and 393.96 is: 543.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    642.72 : 887.04 = 393.96 : x
  2. Step 2: Convert to fraction form
    642.72/887.04 = 393.96/x
  3. Step 3: Cross multiply
    642.72x = 887.04 × 393.96
  4. Step 4: Simplify right side
    642.72x = 349,458.28
  5. Step 5: Solve for x
    x = 349,458.28/642.72
  6. Step 6: Final answer
    x = 543.72

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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.