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Finding the Fourth Proportional to 823.20, 1,241.24 and 720.80

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Solution

The fourth proportional to 823.20, 1,241.24 and 720.80 is: 1,086.84

Step by Step Solution

  1. Step 1: Write the proportion equation
    823.20 : 1,241.24 = 720.80 : x
  2. Step 2: Convert to fraction form
    823.20/1,241.24 = 720.80/x
  3. Step 3: Cross multiply
    823.20x = 1,241.24 × 720.80
  4. Step 4: Simplify right side
    823.20x = 894,685.79
  5. Step 5: Solve for x
    x = 894,685.79/823.20
  6. Step 6: Final answer
    x = 1,086.84

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.