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Finding the Fourth Proportional to 811.20, 1,209.84 and 724.80

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Solution

The fourth proportional to 811.20, 1,209.84 and 724.80 is: 1,080.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    811.20 : 1,209.84 = 724.80 : x
  2. Step 2: Convert to fraction form
    811.20/1,209.84 = 724.80/x
  3. Step 3: Cross multiply
    811.20x = 1,209.84 × 724.80
  4. Step 4: Simplify right side
    811.20x = 876,892.03
  5. Step 5: Solve for x
    x = 876,892.03/811.20
  6. Step 6: Final answer
    x = 1,080.98

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.