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Finding the Fourth Proportional to 820.72, 1,230.78 and 272.78

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Solution

The fourth proportional to 820.72, 1,230.78 and 272.78 is: 409.07

Step by Step Solution

  1. Step 1: Write the proportion equation
    820.72 : 1,230.78 = 272.78 : x
  2. Step 2: Convert to fraction form
    820.72/1,230.78 = 272.78/x
  3. Step 3: Cross multiply
    820.72x = 1,230.78 × 272.78
  4. Step 4: Simplify right side
    820.72x = 335,732.17
  5. Step 5: Solve for x
    x = 335,732.17/820.72
  6. Step 6: Final answer
    x = 409.07

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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.