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Finding the Fourth Proportional to 642.74, 886.56 and 421.88

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Solution

The fourth proportional to 642.74, 886.56 and 421.88 is: 581.92

Step by Step Solution

  1. Step 1: Write the proportion equation
    642.74 : 886.56 = 421.88 : x
  2. Step 2: Convert to fraction form
    642.74/886.56 = 421.88/x
  3. Step 3: Cross multiply
    642.74x = 886.56 × 421.88
  4. Step 4: Simplify right side
    642.74x = 374,021.93
  5. Step 5: Solve for x
    x = 374,021.93/642.74
  6. Step 6: Final answer
    x = 581.92

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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.