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Finding the Fourth Proportional to 642.90, 886.96 and 421.97

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Solution

The fourth proportional to 642.90, 886.96 and 421.97 is: 582.16

Step by Step Solution

  1. Step 1: Write the proportion equation
    642.90 : 886.96 = 421.97 : x
  2. Step 2: Convert to fraction form
    642.90/886.96 = 421.97/x
  3. Step 3: Cross multiply
    642.90x = 886.96 × 421.97
  4. Step 4: Simplify right side
    642.90x = 374,270.51
  5. Step 5: Solve for x
    x = 374,270.51/642.90
  6. Step 6: Final answer
    x = 582.16

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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.