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Finding the Fourth Proportional to 812.20, 1,218.30 and 725.80

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Solution

The fourth proportional to 812.20, 1,218.30 and 725.80 is: 1,088.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    812.20 : 1,218.30 = 725.80 : x
  2. Step 2: Convert to fraction form
    812.20/1,218.30 = 725.80/x
  3. Step 3: Cross multiply
    812.20x = 1,218.30 × 725.80
  4. Step 4: Simplify right side
    812.20x = 884,242.14
  5. Step 5: Solve for x
    x = 884,242.14/812.20
  6. Step 6: Final answer
    x = 1,088.70

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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.