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Finding the Fourth Proportional to 641.95, 886.33 and 421.21

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Solution

The fourth proportional to 641.95, 886.33 and 421.21 is: 581.56

Step by Step Solution

  1. Step 1: Write the proportion equation
    641.95 : 886.33 = 421.21 : x
  2. Step 2: Convert to fraction form
    641.95/886.33 = 421.21/x
  3. Step 3: Cross multiply
    641.95x = 886.33 × 421.21
  4. Step 4: Simplify right side
    641.95x = 373,331.06
  5. Step 5: Solve for x
    x = 373,331.06/641.95
  6. Step 6: Final answer
    x = 581.56

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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.