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Finding the Fourth Proportional to 642.43, 885.74 and 421.00

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Solution

The fourth proportional to 642.43, 885.74 and 421.00 is: 580.44

Step by Step Solution

  1. Step 1: Write the proportion equation
    642.43 : 885.74 = 421.00 : x
  2. Step 2: Convert to fraction form
    642.43/885.74 = 421.00/x
  3. Step 3: Cross multiply
    642.43x = 885.74 × 421.00
  4. Step 4: Simplify right side
    642.43x = 372,892.22
  5. Step 5: Solve for x
    x = 372,892.22/642.43
  6. Step 6: Final answer
    x = 580.44

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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.