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Finding the Fourth Proportional to 812.64, 1,218.48 and 487.80

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Solution

The fourth proportional to 812.64, 1,218.48 and 487.80 is: 731.41

Step by Step Solution

  1. Step 1: Write the proportion equation
    812.64 : 1,218.48 = 487.80 : x
  2. Step 2: Convert to fraction form
    812.64/1,218.48 = 487.80/x
  3. Step 3: Cross multiply
    812.64x = 1,218.48 × 487.80
  4. Step 4: Simplify right side
    812.64x = 594,374.54
  5. Step 5: Solve for x
    x = 594,374.54/812.64
  6. Step 6: Final answer
    x = 731.41

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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.