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Finding the Fourth Proportional to 809.60, 1,215.09 and 665.19

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Solution

The fourth proportional to 809.60, 1,215.09 and 665.19 is: 998.36

Step by Step Solution

  1. Step 1: Write the proportion equation
    809.60 : 1,215.09 = 665.19 : x
  2. Step 2: Convert to fraction form
    809.60/1,215.09 = 665.19/x
  3. Step 3: Cross multiply
    809.60x = 1,215.09 × 665.19
  4. Step 4: Simplify right side
    809.60x = 808,265.72
  5. Step 5: Solve for x
    x = 808,265.72/809.60
  6. Step 6: Final answer
    x = 998.36

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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.