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Finding the Fourth Proportional to 489.96, 731.52 and 421.20

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Solution

The fourth proportional to 489.96, 731.52 and 421.20 is: 628.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    489.96 : 731.52 = 421.20 : x
  2. Step 2: Convert to fraction form
    489.96/731.52 = 421.20/x
  3. Step 3: Cross multiply
    489.96x = 731.52 × 421.20
  4. Step 4: Simplify right side
    489.96x = 308,116.22
  5. Step 5: Solve for x
    x = 308,116.22/489.96
  6. Step 6: Final answer
    x = 628.86

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.