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Finding the Fourth Proportional to 642.09, 886.15 and 393.56

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Solution

The fourth proportional to 642.09, 886.15 and 393.56 is: 543.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    642.09 : 886.15 = 393.56 : x
  2. Step 2: Convert to fraction form
    642.09/886.15 = 393.56/x
  3. Step 3: Cross multiply
    642.09x = 886.15 × 393.56
  4. Step 4: Simplify right side
    642.09x = 348,753.19
  5. Step 5: Solve for x
    x = 348,753.19/642.09
  6. Step 6: Final answer
    x = 543.15

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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.