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Finding the Fourth Proportional to 642.26, 886.45 and 421.13

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Solution

The fourth proportional to 642.26, 886.45 and 421.13 is: 581.25

Step by Step Solution

  1. Step 1: Write the proportion equation
    642.26 : 886.45 = 421.13 : x
  2. Step 2: Convert to fraction form
    642.26/886.45 = 421.13/x
  3. Step 3: Cross multiply
    642.26x = 886.45 × 421.13
  4. Step 4: Simplify right side
    642.26x = 373,310.69
  5. Step 5: Solve for x
    x = 373,310.69/642.26
  6. Step 6: Final answer
    x = 581.25

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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.