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Finding the Fourth Proportional to 642.65, 886.87 and 394.11

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Solution

The fourth proportional to 642.65, 886.87 and 394.11 is: 543.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    642.65 : 886.87 = 394.11 : x
  2. Step 2: Convert to fraction form
    642.65/886.87 = 394.11/x
  3. Step 3: Cross multiply
    642.65x = 886.87 × 394.11
  4. Step 4: Simplify right side
    642.65x = 349,523.44
  5. Step 5: Solve for x
    x = 349,523.44/642.65
  6. Step 6: Final answer
    x = 543.88

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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.