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Finding the Fourth Proportional to 642.55, 886.52 and 393.81

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Solution

The fourth proportional to 642.55, 886.52 and 393.81 is: 543.34

Step by Step Solution

  1. Step 1: Write the proportion equation
    642.55 : 886.52 = 393.81 : x
  2. Step 2: Convert to fraction form
    642.55/886.52 = 393.81/x
  3. Step 3: Cross multiply
    642.55x = 886.52 × 393.81
  4. Step 4: Simplify right side
    642.55x = 349,121.43
  5. Step 5: Solve for x
    x = 349,121.43/642.55
  6. Step 6: Final answer
    x = 543.34

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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.