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Finding the Fourth Proportional to 920.78, 1,380.90 and 271.52

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Solution

The fourth proportional to 920.78, 1,380.90 and 271.52 is: 407.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    920.78 : 1,380.90 = 271.52 : x
  2. Step 2: Convert to fraction form
    920.78/1,380.90 = 271.52/x
  3. Step 3: Cross multiply
    920.78x = 1,380.90 × 271.52
  4. Step 4: Simplify right side
    920.78x = 374,941.97
  5. Step 5: Solve for x
    x = 374,941.97/920.78
  6. Step 6: Final answer
    x = 407.20

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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.