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Finding the Fourth Proportional to 489.12, 733.68 and 215.20

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Solution

The fourth proportional to 489.12, 733.68 and 215.20 is: 322.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    489.12 : 733.68 = 215.20 : x
  2. Step 2: Convert to fraction form
    489.12/733.68 = 215.20/x
  3. Step 3: Cross multiply
    489.12x = 733.68 × 215.20
  4. Step 4: Simplify right side
    489.12x = 157,887.94
  5. Step 5: Solve for x
    x = 157,887.94/489.12
  6. Step 6: Final answer
    x = 322.80

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.