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Finding the Fourth Proportional to 641.57, 885.69 and 420.86

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Solution

The fourth proportional to 641.57, 885.69 and 420.86 is: 581.00

Step by Step Solution

  1. Step 1: Write the proportion equation
    641.57 : 885.69 = 420.86 : x
  2. Step 2: Convert to fraction form
    641.57/885.69 = 420.86/x
  3. Step 3: Cross multiply
    641.57x = 885.69 × 420.86
  4. Step 4: Simplify right side
    641.57x = 372,751.49
  5. Step 5: Solve for x
    x = 372,751.49/641.57
  6. Step 6: Final answer
    x = 581.00

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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.