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Finding the Fourth Proportional to 812.21, 1,218 and 681.60

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Solution

The fourth proportional to 812.21, 1,218 and 681.60 is: 1,022.14

Step by Step Solution

  1. Step 1: Write the proportion equation
    812.21 : 1,218 = 681.60 : x
  2. Step 2: Convert to fraction form
    812.21/1,218 = 681.60/x
  3. Step 3: Cross multiply
    812.21x = 1,218 × 681.60
  4. Step 4: Simplify right side
    812.21x = 830,188.80
  5. Step 5: Solve for x
    x = 830,188.80/812.21
  6. Step 6: Final answer
    x = 1,022.14

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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.