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Finding the Fourth Proportional to 921.80, 1,380.68 and 849.78

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Solution

The fourth proportional to 921.80, 1,380.68 and 849.78 is: 1,272.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    921.80 : 1,380.68 = 849.78 : x
  2. Step 2: Convert to fraction form
    921.80/1,380.68 = 849.78/x
  3. Step 3: Cross multiply
    921.80x = 1,380.68 × 849.78
  4. Step 4: Simplify right side
    921.80x = 1,173,270.00
  5. Step 5: Solve for x
    x = 1,173,270.00/921.80
  6. Step 6: Final answer
    x = 1,272.80

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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.