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Finding the Fourth Proportional to 809.60, 1,212.78 and 663.80

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Solution

The fourth proportional to 809.60, 1,212.78 and 663.80 is: 994.37

Step by Step Solution

  1. Step 1: Write the proportion equation
    809.60 : 1,212.78 = 663.80 : x
  2. Step 2: Convert to fraction form
    809.60/1,212.78 = 663.80/x
  3. Step 3: Cross multiply
    809.60x = 1,212.78 × 663.80
  4. Step 4: Simplify right side
    809.60x = 805,043.36
  5. Step 5: Solve for x
    x = 805,043.36/809.60
  6. Step 6: Final answer
    x = 994.37

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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.