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Finding the Fourth Proportional to 641.22, 885.86 and 420.69

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Solution

The fourth proportional to 641.22, 885.86 and 420.69 is: 581.19

Step by Step Solution

  1. Step 1: Write the proportion equation
    641.22 : 885.86 = 420.69 : x
  2. Step 2: Convert to fraction form
    641.22/885.86 = 420.69/x
  3. Step 3: Cross multiply
    641.22x = 885.86 × 420.69
  4. Step 4: Simplify right side
    641.22x = 372,670.34
  5. Step 5: Solve for x
    x = 372,670.34/641.22
  6. Step 6: Final answer
    x = 581.19

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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.