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Finding the Fourth Proportional to 1,209.46, 1,811.55 and 721.43

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Solution

The fourth proportional to 1,209.46, 1,811.55 and 721.43 is: 1,080.57

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,209.46 : 1,811.55 = 721.43 : x
  2. Step 2: Convert to fraction form
    1,209.46/1,811.55 = 721.43/x
  3. Step 3: Cross multiply
    1,209.46x = 1,811.55 × 721.43
  4. Step 4: Simplify right side
    1,209.46x = 1,306,906.52
  5. Step 5: Solve for x
    x = 1,306,906.52/1,209.46
  6. Step 6: Final answer
    x = 1,080.57

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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.