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Finding the Fourth Proportional to 809.68, 1,212.90 and 808.60

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Solution

The fourth proportional to 809.68, 1,212.90 and 808.60 is: 1,211.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    809.68 : 1,212.90 = 808.60 : x
  2. Step 2: Convert to fraction form
    809.68/1,212.90 = 808.60/x
  3. Step 3: Cross multiply
    809.68x = 1,212.90 × 808.60
  4. Step 4: Simplify right side
    809.68x = 980,750.94
  5. Step 5: Solve for x
    x = 980,750.94/809.68
  6. Step 6: Final answer
    x = 1,211.28

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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.