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Finding the Fourth Proportional to 641.68, 885.75 and 420.68

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Solution

The fourth proportional to 641.68, 885.75 and 420.68 is: 580.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    641.68 : 885.75 = 420.68 : x
  2. Step 2: Convert to fraction form
    641.68/885.75 = 420.68/x
  3. Step 3: Cross multiply
    641.68x = 885.75 × 420.68
  4. Step 4: Simplify right side
    641.68x = 372,617.31
  5. Step 5: Solve for x
    x = 372,617.31/641.68
  6. Step 6: Final answer
    x = 580.69

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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.