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Finding the Fourth Proportional to 642.75, 886.95 and 394.13

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Solution

The fourth proportional to 642.75, 886.95 and 394.13 is: 543.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    642.75 : 886.95 = 394.13 : x
  2. Step 2: Convert to fraction form
    642.75/886.95 = 394.13/x
  3. Step 3: Cross multiply
    642.75x = 886.95 × 394.13
  4. Step 4: Simplify right side
    642.75x = 349,569.17
  5. Step 5: Solve for x
    x = 349,569.17/642.75
  6. Step 6: Final answer
    x = 543.86

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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.