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Finding the Fourth Proportional to 808.20, 1,212.30 and 613.80

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Solution

The fourth proportional to 808.20, 1,212.30 and 613.80 is: 920.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    808.20 : 1,212.30 = 613.80 : x
  2. Step 2: Convert to fraction form
    808.20/1,212.30 = 613.80/x
  3. Step 3: Cross multiply
    808.20x = 1,212.30 × 613.80
  4. Step 4: Simplify right side
    808.20x = 744,109.74
  5. Step 5: Solve for x
    x = 744,109.74/808.20
  6. Step 6: Final answer
    x = 920.70

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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.