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Finding the Fourth Proportional to 820.85, 1,230.86 and 272.84

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Solution

The fourth proportional to 820.85, 1,230.86 and 272.84 is: 409.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    820.85 : 1,230.86 = 272.84 : x
  2. Step 2: Convert to fraction form
    820.85/1,230.86 = 272.84/x
  3. Step 3: Cross multiply
    820.85x = 1,230.86 × 272.84
  4. Step 4: Simplify right side
    820.85x = 335,820.32
  5. Step 5: Solve for x
    x = 335,820.32/820.85
  6. Step 6: Final answer
    x = 409.12

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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.